Poster A: Materials Poster B: Processing Poster C: Properties
173 - Microstructrual Control in Additively Manufactured Titanium Alloys
Alec I Saville, Colorado School of Mines
Controlling microstructures in metallic additive manufacturing (AM) is critical to guaranteeing AM parts meet as-designed specifications. Due to the dynamic thermal histories introduced by AM build processes, maintaining microstructural control has proven a challenge and requires new metallurgical research. Titanium alloys have been especially of interest in metallic AM due to their use in high-waste and high cost traditional manufacturing. Maintaining control of titanium alloy microstructures in AM is inherently complex however. Many alloys exhibit solid-state transformations during build processes, creating cyclic microstructural evolution sensitive to build parameters. Build parameters also heavily influence solidification microstructures, thereby further convoluting how to control the as-deposited and as-transformed microstructures. This work showcases recent efforts to overcome these challenges through evaluating microstructural and crystallographic texture evolution in response to changes in local AM build environment, and evaluating how thermal cycling from AM opens new pathways for control of the solid-state and solidification microstructures.
183 - Dissimilar Metal Interfaces for Reduced Wear of Cladded H13 Hot Forging Punches
Cole J Kuehmann, Lehigh University
Hot forging has current uses for H13 tool steel due to its temperature tolerance, hardness, and toughness. Hot Forging due to the temperature have punches experience significant wear, which at significant cost need to be replaced or repaired. Hybrid AM which is currently being investigated for applying wear resistant cladding, allows for cladding hot forging punches with alloys for better thermal tolerance and hardness. One area of interest is applying these cladding's is the dissimilar metal interface between H13 punches and the cladding material Alloy 625 utilizing electron microscopy techniques. Performing DEFORM simulations of hot forging punches, results with the punch under use experience majority of the temperature rise within 5mm of the surface. The limited depth for the increase in temperature will allow for Alloy 625 with higher hot hardness than H13 above 625°C indicates that it will likely reduce wear and improve the punches tooling life.
188 - Influence of Surface Modification of Powdered Metals on Fabrication of Electrical Laminate Contacts
Nathan S Banner, Penn State DuBois
Previous testing was completed on copper silver graphite electrical laminates. Prior to adding a silver coated copper interlayer; silver diffused into copper faster than graphite, which caused graphite accumulation at the interface creating weak bonding to occur. Upon the addition of a silver coated copper interlayer, counter diffusion occurs between the silver graphite and the silver coated copper interlayer which eliminates graphite accumulation at the interface. Using the scanning electron microscope, it was shown a very small amount of graphite diffused into the interface. Building upon our previous results, we would like to extend the use of this laminate method to other PM materials that are used for electrical contacts namely copper-tungsten and silver-tungsten systems. Laminates using the modified copper powders will be fabricated and the impact of surface modification on mechanical, electrical and wear resistant properties will be assessed. Interlaminar shear strength and electrical performance will be analyzed.
192 - Role of Composition in High Temperature Heat-Treatment Response of Additively Manufactured 17-4 PH Stainless Steel
Derek J Shaffer, Penn State University
Precipitation hardening (PH) stainless steels processed using additive manufacturing (AM) display variations in heat treatment responses and mechanical properties. These variations have been primarily attributed to changes in interstitial element compositions within the allowable ranges. With AM processing of these alloys, composition variations of both interstitial and primary alloying elements combined with microstructures that differ from wrought, impact the thermodynamic stability of important phases such as copper, austenite, delta-ferrite, nitrides, and oxides. This work aims to connect compositional changes in interstitial alloying elements like nitrogen and oxygen as well as other primary elements in AM PH stainless steels to microstructures after hot isostatic pressing (HIP) and solution heat-treatments. A predictable, high temperature heat-treatment response can be established by investigating key aspects of solutionizing and HIP such as the thermodynamic stability of delta-ferrite and copper as well as the influence high temperature phases like nitrides and oxides.
194 - The Effects of High-Speed Mixing
Devin A Carns, Penn State Dubois
The effects of high-speed mixing of iron powders compared to traditional tumbler mixed powders was done to show improvements with the flow properties, mechanical properties (TRS and microhardness) of sintered parts, and other characteristics such as apparent density and porosity. High-speed mixing has shown improvements in almost all characteristics of F-008, FC-0208, and FD-0205 suggesting that using a high-speed mix increases the quality of a product compared to that of a tumbler mixed product. High speed mixing was done at 19,000 rpm for 30 seconds. The powders were compacted to two densities, 6.3 g/cm3 and 6.8 g/cm3 and sintered at 2075 °F in a 90%N2 + 10%H2 atmosphere. Results show that parts made from high-speed mixed powders exhibit higher microhardness and TRS strength compared to parts made from conventional mixed powders. This is attributed to ‘geometrical hardening’ due to particle fragmentation and local deformation at contact areas between particles. This ultimately improves diffusion during sintering. The results of this study suggest that high-speed mixing of powders can be used to improve the properties of typical powder metal parts.
198 - Investigation of the Selective Laser Melting of WC-Reinforcement SS316L Composites
Connor S Ust, Texas A&M University
The purpose of this research is to investigate the effects of the volume fraction of tungsten carbide (WC) and laser power on the processing, structure, and mechanical performance of WC-reinforced SS 316L composite materials, additively manufactured via Selective Laser Melting (SLM) - the primary objectives are improving its wear resistance and bending performance. Steel matrix composites (SMC) have broad applications in various industries, especially in the biomedical field as in-vivo implants, which require good performance in wear and fatigue scenarios. Additive manufacturing allows for the design and manufacturing of SMCs with tailored configurations. This study will enable a better understanding of the additive manufacturing of WC-reinforced SS 316L Steel Matrix Composites by providing insight into the manufacturability and the resulting properties contributing to various engineering applications, like in-vivo orthopedic implants, and the overall advancement of composite materials.
203 - Additive Manufacturing of Aluminum Alloy by Metal Fused Filament Fabrication (MF3)
Luke J Malone, University of Louisville
This research studies metal-fused filament fabrication (MF3) for manufacturing aluminum alloy parts. An aluminum alloy powder-based feedstock with a polymer-binder system will be extruded via capillary rheometry to form a filament. The filament will be used to print green parts that are involved in a two-step debinding process combining solvent and thermal extraction of the polymer binder, then sintered in a partial vacuum. Resulting grain structure, sintered density, and mechanical properties will be characterized and compared to metal injection molded (MIM) specimens. The main objective is to gain an understanding of the MF3 process characteristics and the ensuing material properties and microstructure through carefully designed experiments and computer simulations, therefore creating additive manufactured components from a common lightweight metal. The overarching goal is to enable rapid, predictable, reproducible, low cost, and accurate production of metal parts with 3D features, thereby significantly expanding the current additive manufacturing capability.
208 - Investigation and Comparison of Microstructure and Mechanical Properties of Alloy 625 Parts by Electron Beam Powder Bed Fusion
Julio C Diaz, University of Texas at El Paso
Alloy 625 superalloy is mainly characterized by its strength, high temperature, and corrosion resistance, making it ideal for numerous applications in multiple industries. Metal Additive Manufacturing (AM) is a novel way of designing these components, meeting specific needs with unique geometries. However, additively manufacturing large components is time-consuming. Still, this technology comes with parameters that can be changed to achieve specific goals. This presentation focuses on additively manufacturing a set of Alloy 625 samples with an electron beam melting (EBM) machine and changing layer thickness (50µm vs. 100µm) and heat-treatment processes (as-built vs. heat-treated) to compare the mechanical properties, microstructure, and hardness. Changing layer thickness from 50µm (recommended layer thickness for EBM builds) to 100µm and possibly opting for as-built components instead of heat treated ones may provide sufficient properties to reduce manufacturing time and costs, making metal AM an attractive option for multiple industries when productivity is critical.
216 - Study of Surface modification of Iron Powders That Promote Cold Sintering of Steel Compacts
Austin C Fairman, Penn State DuBois
Previously, it was shown that phosphate coated iron are excellent precursor materials to promote cold sintering and enhance strength of sintered steel compacts. In this study, we show the generic nature of cold sintering by demonstrating the phenomenon using an alternate surface modification technique that involves electroless deposition of copper or iron. The modified iron powders will be used to make steel compositions and the performance of both green compacts and sintered steel will be assessed. Mechanical properties that include tensile and transverse rupture strength measurements will be done and microstructure of the cold sintered sample will be composed against conventional PM steel of similar densities.
217 - Metallographic characterisation of liquid phase sintered PM steels using artificial intelligence
Gabrielle Laramée, Université Laval
The presence of a permanent liquid phase during sintering of press-and-sinter PM components is known to induce important densification of the compacts, as well as notable changes in the microstructure such as rounding and coarsening of porosity. The scale of those changes is strongly related to the proportion of liquid phase, which is in turn a function of chemistry in the case of boron-containing PM steels. This work used a Deep Learning algorithm to segment features of interest, for example pores and solidified liquid phase, visible in metallographic images from a series of samples have different chemical compositions. From the segmented images, meaningful information describing the microstructure was then extracted either through traditional image analysis or using Machine Learning (ML) techniques. The main objective of this investigation was to track quantitatively the effect of chemical composition on the sintered microstructure, while assessing the pertinence of using ML rather than more traditional metallographic descriptors.
026 - Development of Flash Induction Sintering Process and Machine Learning Based Methods: Application to Industrial Diamond Grinding Wheels Manufacturing
Damien Sicard, Laboratoire Interdisciplinaire Carnot de Bourgogne
Diamond Grinding Tools (DGT) hold a central part in high value-added industries and are mainly manufactured by Powder Metallurgy (PM). Indeed, we developed a tailored field assisted sintering process based on induction heating technology. One of the main advantages of this technology is the wide range of grinding wheels which can be sintered due to the process flexibility. With high heating rate, the process could sinter a wheel under five minutes. An experimental study of process parameters and system responses is done for process qualification purposes. In addition to the wheels' synthesis process, it is essential to be able to analyze, compare and characterize the DGT surfaces, especially the diamond grits – matrix interfaces : representative of abrasive properties. One way, is a visual inspection from digital micrographs by a subject expert. However, the complex surfaces morphologies of DGT make manual and standard image processing approaches difficult, time-consuming and error-prone. That’s why, we developed a machine learning computer vision based approach, for automatic diamond grits detection, segmentation and DGT surfaces analysis. Opening the way toward a better understanding of diamond grinding wheel using a data-driven paradigm.
054 - Additive Manufacturing of FeCrCoCuNi High Entropy Alloy via Laser Powder Bed Fusion and Heat Treatment
Ryan Doyle, Oregon State University
High Entropy Alloys (HEA) exhibit unusual properties and are gaining interest as new materials for challenging applications in the aerospace, hypersonic and medical fields. The application of HEAs have been limited by the development and powder production at scale. A recently developed process of plasma spheroidization by 6K, inc. has the potential to produce HEAs at commercial scale. An exemplary HEA powder with chemical composition of 25Fe-18Ni-18Cr-17Co-16Cu (wt%) was produced via mechanical alloying followed by plasma spheroidization. This study characterizes the HEA powder and optimizes laser scanning strategy for the laser powder bed fusion process. Laser powers of 110-200 W and scanning speeds of 200-1000 mm/s were varied in nitrogen atmosphere to determine maximum density. A relative density of 99% was achieved with a laser power of 200 W and scan speed of 600 mm/s. Scanning electron microscopy was utilized to observe the microstructure and elemental dispersion. Energy dispersive X-ray spectroscopy revealed a single ferritic phase of the as printed sample. As printed samples were heat treated at 1050 C for 2 hours followed by furnace cooling to obtain samples with a homogenous composition. Microhardness and tensile tests were conducted to obtain mechanical properties. The microstructures and mechanical properties of the as printed and heat-treated samples were analyzed and compared.
087 - Construction of a Customerized Inkjet 3D Printer
Jing Zhang, Indiana University - Purdue University Indianapolis
Inkjet 3D printing is one of the additive manufacturing processes that utilizes layer-by-layer droplet interaction and solidification to generate 3D components. It has the potential to apply in fabricating ceramic components. In this work, we use an open source design to create a customized 3D inkjet printer. The main goal is to improve the printability by modifying the inkjet extrusion head. Experimentation with the inkjet printer head will be performed to evaluate the printer’s performance with different powder recipes. The compositions of the powder and binder will be optimized. This work provides useful insights to improve our understanding of this promising manufacturing technique.
171 - Visualization of Metallic Alloy Microstructural Evolution Under AM Conditions
Oliver W Hesmondhalgh, Colorado School of Mines
Additive manufacturing (AM) is highly customizable and can be used for the economic production of complex structures. 3D printed metals often contain coarse columnar grains, which may result in directional properties that may be deleterious of advantageous. To achieve the strict specifications needed for some structural applications, control of the microscopic structure and the promotion of grain refinement are crucial. Recent experimental advances allow for the visualization of dynamic solidification events in metals at unprecedented length- and timescales. This work presents the in-situ/ex-situ characterization of microstructural evolution during AM, with the aim of advancing our current understanding of microstructure development under AM conditions, and provides insights into alloy design approaches for AM.
172 - AM Processing and Microstructural Evolution in Nickel-Based Superalloys
Ruben Bladimir Ochoa, Colorado School of Mines
Metal additive manufacturing (AM) has shown promise in producing parts while reducing cost, waste, and increasing geometric complexities over parts produced by conventional manufacturing. A major drawback of AM is the lack of understanding of microstructural evolution and control during the build process, especially during rapid solidification. Local thermal conditions within AM parts favor the formation of columnar grains, which may lead to hot cracking and anisotropy. Thus, understanding the columnar-to-equiaxed transitions relative to AM processing conditions is crucial to control microstructure development. This work focuses on exploring the relationship between AM processing conditions and history on microstructural evolution in nickel-based superalloys.
174 - Finite Element Analysis of Crack Formation within Compacted Powders
Joseph R Wright, Drexel University
The presence of internal cracks within powder compacts directly compromises the structure integrity of the product. In addition to residual porosity, these cracks form by the interruption of interparticle contacts. Here we examine the interaction of these defects with entrapped air which leads to fracture and the formation of macroscopic defects. We study the role of speed of compaction, particle size, and specimen geometry on the stress intensity factor (a direct indicator of defect formation propensity) in this problem using discrete and continuum models. A fracture mechanics approach is utilized to predict the failure system through finite element analysis. The analysis shows that cracks located close to the surface have a stronger effect on fracture. This result is in agreement with defects observed in pharmaceutical tablet compacts.
175 - Microstructural Evolution During Post Processing Treatment of Laser Powder Bed Fusion Alloy 7050 Based Aluminum Alloys
Rupesh Rajendran, Georgia Institute of Technology
High strength 7000 series aluminum alloys fabricated via laser powder bed fusion process are promising candidates for aerospace applications but there has been limited adoption of these alloys due to defects in the final microstructure, such as hot tearing and solidification cracking. Addition of inoculants or nanoparticles has been shown to promote equiaxed grain growth, mitigating such defects. Our work aims to understand the microstructural evolution of AM 7050-based alloys with equiaxed grains during different stages of post-processing treatments – as-built condition, partial annealing, hot isostatic pressing, and solutionizing and ageing. The effect of ageing duration is also studied. The microstructural features like grain size, precipitates, and their distribution have an influence on material properties such as mechanical and corrosion behavior. A case study is presented to show how the difference in microstructure of AM 7050-based alloys lead to difference in corrosion behavior compared to equivalent wrought alloys.
177 - Fabrication of Li-Ion Battery Electrode Filaments Used for Fused Deposition Modeling 3D Printing Process
Eli M Kindomba, Indiana University Purdue University Indianapolis
Additive Manufacturing (AM) has evolved to allow the fabrication of complex structures of various compositions in multiple applications. One promising use of AM is in the three-dimensional printing of optimized 3D battery electrodes through fused deposition modeling. However, a challenge encountered in the 3D printing of battery electrodes involves the necessity to optimize filaments composition and electrochemical performances while maintaining printability and mechanical strength. In this study, we investigate the formulation, printability and material characterization of graphite/polylactic acid (PLA) filaments modified from a recipe in literature. While the graphite/PLA serves as the anode, we also investigate the formulation of cathode filaments. Those filaments are studied and compared based on their printability, electrochemical performance and mechanical characteristics. Through this study, printed electrodes and separator materials can be assembled to form a fully 3D printed battery of complex desired shapes with optimized energy density and sufficient mechanical strength.
178 - Fabrication of Lanthanum Zirconate Based Thermal Barrier Coatings using Spark Plasma Sintering
Tejesh C Dube, Indiana University-Purdue University Indianapolis
In this work, lanthanum zirconate (LZ) based thermal barrier coatings (TBC) are fabricated using the spark plasma sintering (SPS) technique. Three different TBC systems are developed: pure LZ layer, bilayer LZ/Ni-121-1 superalloy, and three-layer LZ/MXene (Ti3C2)/ Ni-121-1 superalloy. Microstructure and phase analyses are conducted using scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Vickers hardness testing is used to evaluate the hardness and fracture toughness of the samples. Fabricating TBCs using SPS provides an alternative means to potentially reduce the fabrication time and costs.
179 - Development of Oxygen Additions for Design of Gas Atomization Reaction Synthesis Processing of Oxide Dispersion Strengthened Alloys
Emma Cockburn, Iowa State University
Mechanical alloying (MA) has been a focus in developing processing methods for oxide dispersion strengthened (ODS) alloys for ultrahigh temperature and/or high-flux radiation tolerant applications, such as nuclear power. MA, while capable of providing “mechano-chemical” mixing of yttria and alloy (Fe- or Ni-based) powders, is time-consuming and may introduce contamination and inhomogeneities. Gas atomization reaction synthesis (GARS) for producing powders for ODS alloy processing provides a cleaner feedstock of powders with Cr-enriched surface oxides and Y-containing intermetallics, creating oxide dispersoids during laser-powder bed fusion additive manufacturing and solid-state friction/stir consolidation by indirect extrusion fabrication. To design the atomization gas composition for GARS process, electromagnetic levitation (EML) experimentation is being developed to examine the effects of gas mixtures on a “macro-sized” droplet to characterize surface oxides and oxide dispersoid generation. EML results will be compared to computational models and atomization results. Funded by USDOE-ARPA-e program through Ames Lab contract no. DE-AC02-07CH11358.
180 - Influence of Impurities in Gas Atomized Aluminum Powder on Strength and Electrical Conductivity of Deformation Processed Wires for Metal-Metal Composites
Dustin T Hickman, Iowa State University
The electrical and mechanical properties of heavily deformed pure Al wire at different levels of purity are well established for Al ingot, as a starting material. However, new research is underway utilizing Al-matrix bi-metallic (Al/Ca) metal-metal composites (MMCs) for increased strength and electrical conductivity that has a matrix phase made from Al powders. However, there is a modicum of material property data for wires made from Al metal powders with differing levels of purity for after consolidation and deformation to final diameter. Thus, this research explores the microstructure evolution and related properties of Al metal powder compared to ingot Al; of varying impurity constituents: iron, silicon, and oxides. The wires have sustained axisymmetric deformation through warm indirect extrusion and subsequent wire drawing to varying levels of deformation. Support from USDOE-Office of Electricity through Ames Laboratory under contract no. DE-AC02-07CH11358.
181 - Impact of a Bi-Modal Distribution on Abnormal Grain Growth in Powder-Based Alnico Magnets
Emily A Rinko, Iowa State University
Growing demand for electric motors to propel electric vehicles has spurred interest in low-cost permanent magnet alloys that decrease reliance on critical materials susceptible to supply-chain disruptions, including Co. Ames Laboratory’s Co-lean alnico exhibits normal grain growth (NGG) during sintering, not abnormal grain growth (AGG) like other, high Co alnico alloys. To improve remanence and energy product for Co-lean, AGG of <001> textured grains parallel to an external magnetic field is desirable. This presentation will focus on the evolution of the grain size and prior particle boundary oxide (PPBO) size/volume fraction at different sintering temperatures to reveal relationships between PPBO evolution and NGG/AGG in Co-lean alnico. We also explore the use of bi-modal distributions at a temperature that revealed ideal balance of grain growth and PPBO size/volume fraction to promote AGG in Co-lean alnico. Work funded by USDOE-OTT-TCF with EERE-VTO support and by KC-NSC through Ames Laboratory contract no. DE-AC02-07CH11358.
186 - Additive Manufacturing of BaTiO3-based Capacitive Sensors
Sakineh Abbasi, Oregon State University
This work investigates the feasibility of additive manufacturing of the Barium Titanate (BaTiO3) dielectric layers on a stainless steel substrate. Samples were produced by different methods such as laser powder bed fusion process and extrusion followed by sintering. The phase compositions in fabricated BaTiO3 ceramics were investigated by X-ray. The surface morphologies and cross-section microstructures were characterized by scanning electron microscopy. The results showed good adhesion between the BaTiO3 layer and 316L SS layers. However, the problem with the laser melting of BaTiO3 was nucleation and propagation of cracks throughout the printing track because of the high heating/cooling rate. Therefore, polyvinylidene fluoride (PVDF) powder and N, N‐Dimethylformamide (DMF) solvent were used as a binder for BaTiO3 which was extruded and sintered at 1400°C. Results demonstrated good adhesion without any cracks. Dielectric properties of sintered BaTiO3 were measured and compared with conventionally manufactured counterparts.
187 - Cold Sintering of Iron Powder Metal
Linsea Foster, Penn State University
Cold sintering of powder metal is novel method for heat treatment at unconventionally low temperatures. This process requires surface modification of individual metal particles, followed by warm compaction. This surface modification typically involves either electroless deposition or acid treatment using some material (which varies depending on the application) over substrate metal particles. The combination of surface modification and warm compaction allows for transient liquid phase sintering of particle boundaries, which accelerates particle rearrangement. The result is high-density compacts with increased strength for both green phase and sintered phase samples compared to controls. The increase in green phase strength offers a means for green machining. Furthermore, a decrease in required processing temperature and green phase machining potentially allows for decreased energy and cost consumption. Lastly, oxidation treatment of cold sintered iron systems may act as a possible method for producing insulating layers over particles that is required in soft magnetic composites.
189 - Effects of High Speed Mixing
Cole s Bressler, Penn State DuBois
Two variants of iron-based powders, F-0008 and FN-0208 were used to study the effects of high-speed mixing on the physical and mechanical properties of sintered parts. The results were compared to traditional tumbler-mixed powders. The high-speed mixed powders showed reduction in the particle sizes and improvements in properties such as flow rate, apparent density, porosity, and TRS strength. The parts were compacted to two densities, 6.3 g/cm3 and 6.8 g/cm3
191 - A Review of the Effect on Compaction and Sintering of Various Lubricants that are Commonly Used in Powder Metal Processing.
Jacob P. Feldbauer, Penn State University
Lubricant is required in the compaction process to reduce ejection forces, maintain product quality, and increase tool life; likewise, different amounts and types of lubricants are needed to address issues of green density and product geometry. Although the lubricants are required for the compaction process, they must be removed to allow proper sintering. In this work, the effect of three commonly used lubricants are reviewed throughout the process. A look at the pro’s and con’s of each lubricant in each stage of the process will help to shed light on the best application for the type of lubricant and the final effects these choices may have on the final product quality.
193 - Sinter Brazing and Effects of Surface Modifications on Braze Joint Strength
Caleb H. Thompson, Penn State University
Sinter brazing is a process in powdered metal industry whereby two parts are bonded via a filler/braze metal during sintering. This study investigates the effects of braze gap and surface roughness on braze strength. Standard FC-0208 powder was pressed to three densities of 6.6, 7.0, and 7.0 g/cc to make transverse rupture strength (TRS) bars that were sinter brazed using three gap widths, 0.001”, 0.003” and 0.005”. Two types of brazing materials were used in the study. Since powdered metal parts are porous, it is important that their density is high enough to prevent loss of braze material due to infiltration (that is, all the liquid braze flowing into the part). A mathematical model of strength vs. gap width and surface roughness will be presented.
196 - Attempting Near Wrought Density in PM Steel Using Micro Ingot Double Press Double Sinter Route Coupled with Hot isostatic Pressing and Proprietary Intensive Quenching
Nicolette P Brossard, Penn State DuBois
The purpose of this research is to investigate microstructural mechanisms operative under isostatic pressing and proprietary heat treatments that can help achieve near wrought density and improved mechanical properties of a low alloy nickel molly steel powdered metal processed by micro-Ingot double press double sinter (MI-DPDS) route. Specifically, porosity, density, fatigue life, transverse rupture strength and hardness are evaluated and compared. Cross sectional porosity mapping of sintered compacts conducted using scanning electron microscopy show regions close to the edges of the sample had low porosity while the center region had relatively higher porosity in MI-DPDS. With higher density, mechanical properties of the material are improved. We attempt to analyze, quantify and report underlying microstructure property relationships and the size evolutions of the porosity throughout the sample under different processing conditions that affectively enable the sample to reach close to wrought density as well as increase its mechanical properties.
200 - A Modified 7068 Aluminum Alloy Designed for Laser Powder Bed Fusion
Brandon N Fields, University of California, Irvine
Many additively manufactured alloys exhibit higher strengths when compared to compositionally identical alloys processed via conventional processing routes. However, this enhancement is not observed in 7xxx series Aluminum alloys. These alloys exhibit two complications when printed via Laser-Powder-Bed-Fusion: significant evaporation of strengthening elements from the melt pool and crack formation due to hot tearing during solidification. To address these issues, we have designed and developed a modified Al-7068 alloy with increased alloying accounting for evaporation; in addition, TiC nanoparticles dispersed within the powder eliminate dendritic solidification and restrict grain growth, thus avoiding hot tearing. Printing parameters are optimized for minimum porosity. Trends in alloying elements’ evaporation with laser energy density are quantified using inductively-coupled-plasma mass-spectrometry. The microstructure and mechanical behavior in as-printed and T6-heat-treated conditions are characterized using x-ray diffraction and scanning electron microscopy. The experimental work was complemented by CALPHAD phase stability calculations.
201 - 3D Printing of Non-Ferrous alloys via Metal Fused Filament Fabrication (MF3)
Kameswara Pavan Kumar Ajjarapu, University of Louisville
Fused Filament Fabrication (FFF) is a primitive additive manufacturing (AM) technique to fabricate intricate polymeric parts in a quick and cost-effective manner. Powder fused filament fabrication (PF3) 3D printing process utilizes powder-filled polymer filaments and a combined Fused filament fabrication (FFF) and sintering processes to fabricate complex metallic and ceramic structures. Powder filled polymeric feedstocks and filaments were prepared, which were subsequently 3D printed. Non-ferrous metallic alloy green parts were sintered and characterized to understand the physical and mechanical properties of the final part. The current work aims to address critical knowledge gaps to enable a seamless transition from Fused Filament Fabrication (FFF) to Metal Fused Filament Fabrication (MF3) by utilizing fundamental concepts of Powder Metallurgy (PM) and Metal Injection Molding (MIM). Additionally, process maps and models were inculcated to predict powder-polymer material properties critical to perform process simulations software.
204 - Printing CuO Paste with Laser Processing: A Novel Approach to Printed/Flexible Electronics
Sihan Zhang, University of Louisville
Printed electronics has drawn research interest due to its flexibility, cost-effectiveness, and eco-friendliness, when compared to its competitors in traditional methods. This research combines 3D printing CuO paste with laser processing to fabricate conductive patterns on various substrates. Commercially available CuO paste was printed with a custom-made auger print head and followed by 500 mW laser processing. The reduction of CuO to Cu was achieved by laser processing, which does not require inert or reductive gas atmosphere. The CuO paste was characterized with XRD, TGA-DSC and UV-vis spectrometer. The conductive Cu lines were characterized with optical microscope and the resistivity was measured using a probe station. Both the print head and the laser module are compact and can be mounted on a multi-tool 3D printer. The overarching goal is to develop a flexible, rapid, and cost-effective method for printed electronics.
207 - Fatigue Surface Imaging
Alex De La Cruz, University of Texas at El Paso
In Additive Manufacturing (AM) surface finishing contributes greatly to the overall behavior on how the metal alloy reacts to stress and failure. Using a Laser Powder Bed Fusion (L-PBF) machine, we printed various samples with different parameters using Ti-64 powder to analyze their as-built surface to characterize and test performance. The understating of the as-built surface is crucial since not all AM components can be machined. The performance was determined by running four-point bend tests on each sample. The samples undergo repeated flexural loading with a frequency of around 10 hertz. After failure, the samples are surface scanned to identify any deformation that lead to sample fracture. A correlation of surface finish, build parameters, performance, and defects were analyzed to further predict the as-built components.
209 - Binder Jetting of 316L Process Simulation Tools Evaluation
Victor A Medrano, University of Texas at El Paso
With this investigation a new Binder Jet simulation tool was tested. To achieve this, a dimensional test artifact geometry was built and inspected to compare it with the predicted build simulations results. Additionally, the artifact has been analyzed, built, and inspected for a prototype/demonstration part. Binder Jet has become one of the most popular AM technologies over the years, although some disadvantages are the time and money consuming analyzing and performing the sintering parameters and processes; this software will be money and time efficient for the industry. The test artifact analysis includes the dimensional measurement inspected by hand using calipers and gauges. The simulation software was used in an initial evaluation of the test artifact geometry to identify areas of concern in the build, and document the strengths and weaknesses. The purpose is to demonstrate the efficiency of the Binder Jet Software in predicting material behavior during AM process.
211 - Alkaline Roasting and Hydrolysis for the synthesis of Titanium Dioxide Powder
Nicholas B Engstrom, University of Utah
Titanium is one of the world's leading materials in terms of reducing environmental impacts and improving the physical properties of equipment. While titanium metal and its alloys are very important materials, titanium dioxide is equally important for its use in pigments. The biggest drawback to producing titanium dioxide and titanium metal is that it is a high energy and high cost process. The industry standard Kroll process is the only widespread method for producing titanium and requires titanium chloride as a feedstock, a form that isn’t naturally occurring. On the other hand, the emerging HAMR process can produce titanium powder from titanium dioxide, a form plentiful in titanium ore. Alakine Reduction, Hydrolysis or ARH is an emerging process that can remove impurities from titanium ore and produce highly pure titanium dioxide for use in pigment applications or the HAMR process. It is far cheaper and less polluting than it’s alternatives.
212 - Current Research in Binder Jet Printing of Titanium Powders
Nathan A Jump, University of Utah
Binder Jet (BJT)printing has recently emerged as a feasible manufacturing method for small to large scale parts, but at the current moment, the full capabilities of this technology are restricted by the materials available. Titanium is one of the most desirable materials used in manufacturing due to its low density, high strength, high elongation %, and corrosion resistance, yet at this time the material cannot successfully be utilized within the BJ system. This discontinuity exists due to titanium having a high affinity for both carbon and oxygen impurities. These impurities, which are abundant within the polymeric binders utilized in the BJT system, can significantly reduce the highly desired mechanical properties of titanium. Current research is being conducted to produce Ti64 parts on the BJ system, with relatively low carbon and oxygen contents. The oxygen and carbon pickups from each step are investigated.
214 - A comparison of the Mechanical Properties and Production of Powder Metal Components made with Intralube ETM and Sintered Using Two Different Sintering Approaches.
Scot E. Coble, Penn State DuBois
Intralube Etm sees regular use in the compaction of higher density powder metal components. Although it is seeing more and more use, little work has been done to review the impact that this lubricant has on the sintering process. Here, the effect of this lubricant as a function of compact density, lubricant amount, and sintering method will be reviewed. A look at the impact on the physical properties, production rate, and quality of the final compacts will be demonstrated.
215 - Effect of grain distribution and controlled heat treatment in the micro ingot Double Press Double sintered Process towards achieving improved mechanical properties
Dakota C Stormer, Penn State DuBois
Unscreened and unannealed 100% pre-alloyed steel powder 4600V were processed under controlled conditions following recently proposed modified DPDS route. Densities of 7.3- 7.5 g/cc were achieved by pressing under different time, temperature and pressure combinations to optimize the process. Optimized samples were then analyzed for the role of microstructure and grain distribution on improvement of final density and mechanical properties. Using a micro hardness, mapping of localized hardness on large and small grain size clusters of the etched sample were conducted. Samples were then post processing using controlled heat treatments and quenching, and evaluated with XRD measurements for residual stress state on the sample surface under different compaction pressures. This was correlated with the overall densification and role of multi modal grain size and compressive surface stresses on improved mechanical properties. Mechanical characterization was done to evaluate improvements in strength by TRS testing, microhardness and improvement in fatigue life of the samples.
039 - Elemental Characterization of Additive Manufacturing Feedstock Powders Using an Innovative Technology
Ellen Williams, Exum Instruments
This poster will demonstrate a new technology for characterizing additive manufacturing feedstock powders, Laser Ablation Laser Ionization Time of Flight Mass Spectrometry (LALI-TOF-MS). Currently, feedstock elemental characterization requires multiple analytical techniques. Inductively Coupled Plasma Mass Spectrometry or Atomic Emission Spectrometry can measure a material's metallic and residual constituents, however, these methods require a highly trained analytical chemist to execute proper sample preparation procedures, signal interference corrections, and calibration. These methods also fail to measure low-mass elements like carbon, nitrogen, and oxygen. Thus, quantifying these elements requires additional methods, such as inert gas fusion and combustion. Addressing many challenges of other analytical instruments, LALI-TOF-MS combines trace-level detection capabilities for virtually the entire periodic table with intuitive, seamless operations. It uses two lasers to first ablate, or liberate, material from the sample's surface and then ionize that material in a second step. By analyzing powder samples directly, it eliminates complicated sample preparation procedures. After ionization, the particles move through the optics system to the Time of Flight (TOF) mass analyzer, which measures the time required for ions of different masses to impact a detector. A full mass spectrum is generated for each laser shot, facilitating multielement quantification.
170 - Using Machine Learning Techniques To Characterize Powder Behavior and Surface Roughness in Powder Bed Fusion AM
Srujana Rao Yarasi, Carnegie Mellon University
Characteristics of the powder feedstock such as particle size distribution, sphericity, and morphology affect the flowability of the powder and the layer density distribution of the powder bed. The use of computer vision and machine learning tools in the additive manufacturing domain have enabled the quantitative investigation of qualitative factors like powder morphology. The use of Convolutional Neural Networks (CNN) to generate feature descriptors is proposed as part of a framework to generate powder morphology distributions that describe morphological characteristics of the powder. Similarly, the measurement of surface roughness is an image data rich problem that is benefited from characterization with machine learning techniques. There are multiple factors that affect surface roughness including powder size and process parameters. ML techniques are used to correlate these different factors and surface roughness metrics.
176 - Effect of Post-processing on the Microstructure and Mechanical Performance of Laser Powder Bed Fusion Hydride-dehydride Ti-6Al-4V Alloy
Mohammadreza Asherloo, Illinois Institute of Technology
Hydride-dehydride Ti-6Al-4V with non-spherical morphology and size of 50-120 μm is laser powder bed fusion (LPBF) processed to 99.8% density; remnant pores are eliminated by hot isostatic pressing (HIP). Process optimization was conducted on power-velocity-hatch spacing parameters with an increased build rate ratio of two. Microstructural observations indicate formation of columnar β grains with acicular α/α′ phases in as-built condition, while the HIPed specimens show partial decomposition of α′ to α+β inside the prior β grains. The as-built condition showed hardness 370 HV0.3, yield strength (YS) 1220 MPa, and ultimate tensile strength (UTS) 1310 MPa; after HIP treatment, the values were hardness 337 HV0.3, YS 1070 MPa, and UTS 1125 MPa. The average roughness of the as-built/HIPed samples was Ra=25.9 μm, but this decreased to Ra=1.7 μm after mechanical grinding. Fatigue testing under with R=-1 showed that the HIPed-ground condition increased the life by 10 times over the as-built condition.
182 - Investigation of Microstructure Response of 316L and 17-4 Stainless Steels to Selected Micro-AM Processes
Chia-Chun Chao, Lehigh University
There is a strong trend for fabrication of micro stainless steels parts by various additive manufacturing (AM) processes. The subject of the presented research is to understand how microstructure of 316L and 17-4 stainless steel responds selected micro-AM processes. Both materials were processed by the Binder Jet and Direct Metal Laser Sintering processes. One of the major goals of our research was to establish the final density of the printed parts. The powder used for printing micro parts is around 20μm in diameter, which is optimal size for macro additive manufacturing processes. The microstructures of these sample were analyzed via Light Optical Microscopy (LOM) and Scanning Electron Microscopy (SEM). The X-Ray technique was used to analyze the chemical composition of each sample from both AM processes.
184 - Investigation of the Microstructure and Mechanical Properties of Printed Alloy 4046 and Alloy 6061 through High Laser Power Selective Laser Melting Process
Mahsa Navidirad, Lehigh university
Although, selective laser melting (SLM) technique is commonly used for fabrication of selected high strength Aluminum alloy parts, it is challenging in producing sound parts due to low flowability and high thermal conductivity of the powder. However, selection of a proper SLM process parameters can achieve printed parts with desired microstructure and consequently mechanical properties. In this study, the influence of SLM process parameters including laser power, point distance, and scan speed on final quality of as-built alloy 4046 and alloy 6061 was investigated. Solid 10 x 10 x 10 mm3 samples were printed for microstructural characterization using both light optical and scanning electron microscopy techniques. Moreover, compression and tensile test samples were printed using the same processing conditions for both powders to evaluate mechanical properties of the printed material.
185 - Relating Mechanical Properties of Additively Manufactured Aluminum Alloys with Porosity
Kazuki Watanabe, Lehigh University
It is a widely known problem that additively manufactured aluminum alloys have many defects reducing their potency in mechanical strength. One main defect is the pores that form during the printing process which leads to other defects such as cracks. These pores vary in their frequency based on the machines, powders, and environment they were manufactured in. By relating the average percent of pores in a sample to its tensile and compression tests, it can serve as a basis for more accurately predicting the mechanical properties of the same alloy before testing. Having these relations available for alloys with this common problem, such as the 6xxx series, would be useful for isolating other instances of defects and estimating variation in mechanical properties based on the machine and the environment by measuring its porosity.
190 - Kinetics and Diffusion of Carbon Incorporation into PM Copper Steel Components Subjected to Impregnation with Inorganic Sealant prior to Heat Treatment
Austin Klinger, Penn State DuBois
Powder metallurgy components formed from MPIF standard copper steels are widely used for a variety of structural applications due to its excellent balance of mechanical properties, relative processing simplicity and low fabrication costs. Within industrial practice, optimal operational properties expected for these components are achieved through both the as-sintered and heat treatment states. During the heat treatment process and associated intensive cooling, heterogeneous metallurgical phase changes, density gradients, and variance in carbon incorporation can often lead to measurable size variation of the hardened component. The carbon chemistry distribution within the heat-treated copper steel is dependent on the initial powder carbon content as well as on the carbon potential of the heat treatment furnace atmosphere. The variation of copper solubility during heat treatment along with carbon diffusion appear to be the significant contributing factors for the final properties of the copper steel, however, recent research indicates some negative effects of carbon variations and residual porosity can be mitigated by impregnation with inorganic sealant (IS) applied prior to the heat treatment process. This paper looks at the dimensional stability, apparent and micro indentation hardness along with microstructural features of several copper steels with respect to density and initial powder carbon content and demonstrates the ability to tailor microstructural carbon through heat treatment.
195 - Investigation of Corrosion Performance of Standard PM Stainless Steels with Secondary Processing for Enhanced Corrosion Protection
Daniel P Stauffer, Pennsylvania State University at DuBois
Corrosion is a concern impacting any iron-based material. According to the National Association of Corrosion Engineers, global costs due to corrosion are estimated to be > $2.5 trillion USD annually. To combat this, stainless steel materials or specialized coatings and plating are selected for environments where standard iron-based materials would corrode and degrade. Powder metallurgy is no exception, where great care is taken for materials selection and process control to optimize corrosion protection. In this paper, corrosion testing of powder metallurgy austenitic and ferritic stainless-steel material was conducted in regard to ASTM test conditions to investigate the impact of secondary process operations on corrosion performance. Baseline results for standard powder metallurgy materials is presented and visually used as a comparison to determine a factor of performance for the secondary operations evaluated. Radial crush strength and apparent hardness as well as microstructure measurements were also performed to investigate the impact of processing on mechanical properties of the modified stainless-steel materials.
199 - An Investigation of the Mechanical Properties of Tantalum Cold Sprayed Coatings via Micromechanical In-Situ Testing
Mahsa Amiri, University of California, Irvine
Understanding the underlying mechanisms of how feedstock powder properties can influence the properties of cold sprayed deposits are crucial for obtaining high quality bonding. Cold spray deposits using two feedstock powders of tantalum with different particle sizes and distribution and different hydrogen contents were created. Mechanical properties of the deposits and their feedstock powders were investigated through in-situ micro-mechanical tests. Microstructural analysis via SEM and STEM were done to fully understand the observed behaviors for the samples during mechanical tests. Definitive trend between the changes in mechanical properties and hydrogen content was not inferred. Variations in the mechanical response of the samples were, however, attributed to the changes in the defect networks and quality of the inter-splat bonding. The feedstock powder with larger average particle size and wider distribution resulted in a coating with inferior bond quality and higher porosity percent and cracks.
202 - Generative Design and Topology Optimization based 3D printing via Metal Fused Filament Fabrication (MF3)
Saleh Khanjar, University of Louisville
Metal fused filament fabrication (MF3) 3D printing technology is a combination of fused filament fabrication and sintering process. Generative design and topology optimization tools typically identify optimal distribution of material for a part while simulating the part’s behavior when subjected to expected loads. Such tools have been utilized to minimize material consumption and weight, without compromising on the performance of the parts printed using different AM technologies. However, in contrast to other AM technologies, MF3 technique involves debinding and sintering the 3D printed green part to achieve high density final product. This work implements generative design and topology optimization software to investigate its limitations in MF3 3D printing. Additionally, the effect of design optimization on structural integrity of parts 3D printed via MF3, from green to sintered state was studied. The application of design optimization to MF3 revealed promising results, addressing component efficiency and sustainability.
205 - Miura-Ori Based Metallic Structure for Large Deformation via Additive Manufacturing
Vanshika Singh, University of Tennessee/Oak Ridge National Laboratory
Nature provides notable instances where they respond to environmental changes without any external devices. Based on this, we propose developing structures that can respond to changes in boundary conditions such as temperatures without leveraging unique materials (shape memory alloy or polymers) and external devices (sensors or actuators). Origami has previously shown promising results for large deformations via different materials like polymers and bio-materials in various applications. We propose to leverage Miura-ori, a type of origami design, to study the role of origami for metallic structures. Since metals provide a lesser elasticity range, we hypothesize to leverage geometric non-linearity for large strains. To demonstrate this, we designed the origami mountains and valleys via metals under mechanical compressive load to achieve high strains in the XY plane and simulate the results via Finite Element Analysis. We leveraged Laser-Powder Bed Fusion (Additive Manufacturing) based techniques to realize these complicated structures.
206 - Effects of Aging and Heat Treatments on Alloy F357 (AlSi7Mg)
Kevin Caballero, University of Texas at El Paso
Heat treatments are commonly applied to some aluminum alloys to modify its properties. For example, ASTM F3318 standard addresses some widely used heat treatments for AlSi10Mg, a popular material for casting. However, currently there is no standard for the usage and heat treating of F357 (AlSi7Mg) alloy, one of the most used aluminum alloys in additive manufacturing. This work present mechanical properties of F357 specimens fabricated with laser powder bed fusion and subjected to heat treatments. As-build, stress-relief, T6, HIP, HIP+T6 heat treatments conditions were applied to tensile specimens and tested. Furthermore, with interest of the alloy performance in service conditions, the specimens were subjected to artificial thermal aging for 100hrs and 1000hrs and their mechanical properties determined. Finally, remarks on the comparison between the heat treatments and the effect of thermal aging on them will be presented.
210 - The Effects of Printing Parameters in Ti-6Al-4V Under Cyclic Flexural Loading
Brandon Ramirez, University of Texas at El Paso
Additive manufacturing via Laser Powder Bed Fusion (LPBF) has already been proven to be a revolutionary technology. For example, the use of Ti-6Al-4V, a popular titanium alloy due to its favorable strength to weight ratio, has already been implemented in the aerospace industry for various parts. However, the validation of quality in additive manufactured parts has always been an issue of concern, specifically under cyclic flexural loadings. To further investigate these conditions, Ti-6Al-4V samples were printed using LPBF with various processes parameters to include the optimal printing parameters from previous outside literature as well as samples with defects such as lack of fusion and keyholing. Cyclic loading experiments under a 4-point bending fixture were then conducted to investigate the effects of such defects and validation of additive manufactured components. Data from the experimentation is presented and categorized by printing parameters to compare their fatigue life under flexural conditions.
213 - Particle Size & Shape Effects on Powder Behavior and Cold Spray Processability after Environmental Exposure
Jack Grubbs, Worcester Polytechnic Institute
Environmental exposure of metal powder to unregulated atmospheric conditions during handling and storage can be detrimental to powder properties and behavior, such as flowability and spreadability. Degradation of properties prior to use in an additive manufacturing (AM) technology, such as cold spray (CS), may result in adverse effects on powder processability and in turn part performance. This study aims to investigate the effects of particle size/shape characteristics on Al 2024 powder behavior and CS processability after controlled exposure to humid conditions. Semi- and ultra-spherical Al 2024 powder of variable size distributions will be exposed in an environmental chamber for extended durations. Each powder sample will be characterized for morphology, size, moisture content, and flowability. Subsequent processing via CS will assist in evaluating AM processability changes. Guidance on proper powder handling and storage protocols for AM processing will be developed with an emphasis on particle size/shape characteristics.