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Tuesday Sessions
3:15 p.m. - 4:30 p.m.

 

PowderMet          AMPM          Special Interest

PowderMet Abstracts

 

 

PM-6-1   Effect of Additives, Density & Cooling Rate

 

096 - Study of Mechanical Properties Using New Blends of Cost Effective Lean Mo Copper Alloy 
Xin Yin, Burgess-Norton Mfg. Co.

Current development of ‘lean’ low alloy powder metallurgy (PM) is aimed at delivering cost-effective components. Molybdenum (Mo) is a popular alloying element because it improves mechanical property, hardenability, while maintaining compressibility in PM alloys.  Copper as an additive also improves the as-sintered strength and hardness properties. Combination of Mo and Cu greatly increase the hardenability and mechanical properties of the PM steels.   Previous studies, “Effect of molybdenum content in PM steels” (Lindsley) have shown increase in mechanical properties when copper and nickel was admixed to FL-39XX, FL-40XX, FL-44XX ,and FL-49XX.   This paper modifies on previous study by only using copper and by further leaning out the blend with addition of unalloyed PM iron powder. Mechanical properties of the new ‘lean’ low alloy was studied in as-sintered condition.

108 - A Review of the Effect on Compaction and Sintering of Various Lubricants that are Commonly Used in Powder Metallurgy Processing
Jacob Feldbauer, Penn State University DuBois

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.

142 - Microstructure Characterization of High-Density Sinter Hardened Steel
Amber Tims, PMT, North American Höganäs Co.

Sinter hardening is a process that uses accelerated cooling following sintering in combination with required alloying elements and contents to achieve a desired metallurgical matrix for powder metallurgy (PM) components. Sinter hardened materials normally consist of prealloyed low-alloy steel powder admixed with graphite and copper.  Understanding the responses of martensitic phase formation with different graphite and copper additions is crucial to the selection of suitable sinter hardening material compositions, especially when the material is sintered at different densities. Since sinter hardening occurs during rapid cooling, the density of components plays an important role in achieving desired microstructures. Parts at higher density contains more heat energy that could affect the cooling rate compared to the one at lower density. In this paper, a series of studies was performed to investigate the sinter hardening responses of a FLC-4608 sinter hardened material compacted at different densities with various graphite and copper additions.   


 

PM-6-2   MIM Processing & Materials II

 

004-R - Titanium Atomization Technology; Developments Spanning Over 60 years
James Sears, Amaero Additive Manufacturing

Over the course of the last 60 years there have been many developments in the techniques used to atomize Titanium alloys. The reasons for using powder Titanium (PM-TI) for part fabrication has been well established, i.e., the associated reduction in fabrication costs (e.g., reduction in Buy-to-Fly ratio). A major impediment to a wider acceptance for the use of PM Ti has been the high cost of powder production, especially due the shift to finer particle sizes. The original need for fine powder was the result of demand from the MIM industry due to developments of Titanium applications. Now, with the recent focus on Additive Manufacturing, especially Laser Powder Bed Fusion (LPBF), the market for fine Titanium alloy powder has steadily increased. The historical developments in Titanium atomization will be discussed and how it relates to in increased demand from the MIM and AM industries.

135 Advancing Metal Injection Molding Materials and Properties
Timothy McCabe, OptiMIM

Developments to produce materials and advance properties of Metal Injection Molding and Binder Jet sintered for critical applications.  Will outline the capabilities to compete with wrought materials.  Will discuss results for 17-4PH stainless, carbon steels and tool steels.  

080 - Notch Sensitivity and Mean Stresses of MIM Steel Grades via FEA Analysis
Markus Schneider, GKN Sinter Metals Engineering GmbH

In the last years two MIM steel grades (MIM 8620 case-hardened and MIM 100Cr6 hardened) were characterized in terms of its fatigue performance under a variety of loading conditions. Due to their heat treatment histories and (surface) carbon contents macrohardness values of above 600 HV 30 were achieved. Generally, the ductility is inversely affected by the carbon content. Therefore, the characterization of MIM steel grades having a lower carbon content is of interest. A very commonly used low-alloyed MIM steel grade is MIM 42CrMo4 (AISI 4140). Its lower carbon content yields to a good strength and ductility combination which makes that MIM steel grade interesting for all machinery and automotive components. This paper discusses the combined effect of notches and mean stresses on the fatigue response. Moreover, support factor diagrams are presented to approximate the notch sensitivity of MIM steel grades via FEA structural stress analysis. 

 

AMPM Abstracts

 

 

AM-6-1   Novel Material Development

 

125 - Rapid Alloy Discovery Enabled by Additive Manufacturing
Nicolas Argibay, Ames Laboratory

As the sophistication and quality of metal additive manufacturing (AM) continues to improve, research emphasis has shifted from feasibility studies towards process optimization. However, significant challenges remain to producing near net-shape parts with mechanical properties that compete with traditional manufacturing techniques and alloys. Achieving desirable microstructures via AM using traditional alloys remains a challenge due in large part to the inherently extreme thermal conditions; for example, a century of steel manufacturing optimization has led to processing methods that are strongly misaligned with the rapid melting and solidification typical of AM.  We present results from recent efforts to accelerate alloy design for AM rather than process optimization of existing alloys that may identify only tight processing windows. We also demonstrate how high-throughput surface mechanical testing methods are an effective alternative to traditional methods for the determination of structure-property relationships that aid alloy design. Supported by USDOE-EERE-AMO through Ames lab contract DE-AC02-07CH11358.

160 - Production of High-Grade Metal Powder for Additive Manufacturing by Using the Powder Atomization Plant
Yannik Wilkens, SMS Group GmbH

This presentation will detail how a  full-scale powder atomization plant for the production of high-grade metal powders is operated to gain detailed operator and production expertise to develop and produce high quality AM powders. By understanding the different influencing factors during atomization and the influence of powder properties on the additive manufacturing process, the powder atomization facility is able to produce powder with improved quality and increased output.  In this presentation, the Powder Atomization Plant and its technical features are described in detail to show the correlations of the powder processing and best results of the laser based powder bed fusion printer. Combining a high utilization grade of metal powder and the right particle size and shape for additive manufacturing at highest quality, the new plant concept demonstrates customers how to become the leading supplier of the AM industry.

149 - Additive Manufacturing (AM) Results of Multi-Principal Element Alloy (MPEA) Design Work
Iver Eric Anderson, FAPMI, Ames Laboratory

Further progress permits microstructure and tensile properties to be reported on as-built and heat treated samples made with AM by directed energy deposition (DED) of gas atomized feedstock powder composed of an advanced MPEA alloy, 25Al-9Fe-43Ni-9Co-9Cr-5Cu (at.%). This alloy, termed Emmalloy, was from a series of MPEA compositions that were designed with modeling based on an all-electron theory, addressing chemical disorder, where valence-electron concentration is a key determinant for tuning elemental concentrations. “Spider” plots based on binary, piece-wise formation energies narrowed the MPEA composition. Down selection included the need for sufficient ductility from a significant fraction of FCC crystal structure and verification of a fairly equiaxed chill cast microstructure without needle-like phases. Post-build heat treatment was suggested by appearance of precipitates in stress-relieved microstructures. Reported results will consist of tensile properties in as-built and heat treated conditions and corresponding microstructures. Funded by USDOE-EERE-AMO program through Ames Lab contract no. DE-AC02-07CH11358.


 

AM-6-2   Powder Properties & Rheology

 

229 - 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.

002 - Evaluating Spreadability of Feedstocks for Powder Bed Fusion Using Novel Techniques and Powder Rheology
Amalia Thomas, Freeman Technology LTD

The quality of the final product of Additive Manufacturing (AM) Powder Bed Fusion (PBF) processes is affected by the ability to spread powders in thin layers, typically a few particle diameters deep. It is important for the formed layers to be uniform, consistent and predictable, but different powders perform differently in the spreading process. The consistency and uniformity of the density and thickness of the spread layers are influenced by many factors, including physical properties of the particles and bulk behavioural properties such as flowability, density and permeability. In this presentation we consider the demands of a typical spreading/recoating operation in a PBF process and the challenges of assessing powders for suitability. A method for quantifying spreading performance based on a laser profiler is proposed with data presented for several typical feedstock powders, both metallic and polymer. We show a method for quantifying powder layer quality with high enough resolution to resolve individual particles, but also with a wide enough measurement range to identify macroscopic features such as streaks and layer thickness inconsistencies, over length-scales comparable to typical build platform sizes. Moreover, the method proposed is un-intrusive and relatively accessible in term of cost, amount of material required and ease of use, optimising the trade-off between practicality of results and accessibility.

233 - Electrostatic Charging and Its Impact on Powder Flowability
Louis-Philippe Lefebvre,  National Research Council Canada

It is recognized that the electrostatic charging can affect the flowability of powders.  While particle charging is usually more important for nonconductive materials, it has been observed that electrostatic (i.e. coulombic) forces can also affect the flow behavior of metallic powders.  Tribocharging is generally associated with the exchange of electrons arising during the friction of dissimilar materials but charging between particles of the same nature has also been reported in the literature. In this context, the interparticle interactions are affected by charge distribution (i.e. the attraction coming from particles having different polarities) which are difficult to measure experimentally. Powder flowability and rheology have recently been used to demonstrate the effect of coulombic forces on particle interaction and flowability. This paper presents an evaluation of the effect of tribocharging on the rheology of different metallic powder (Inconel 718, aluminum, titanium, stainless steel). Results show that the nature of the materials is important and may affect significantly the rheology of the powders.


 

AM-6-3   Metal AM Testing & Evaluation I

 

2363D Printing of Supportless Structures using Multi Axis Direct Metal Deposition Process 
Farhad Ghadamli, DM3D Technologies

Multi-axis with Directed Energy Deposition (DED) in additive manufacturing is a powerful tool for building parts that traditional three-axis 3D printing cannot achieve. Direct Metal Deposition (DMD), which is a form of DED technology, utilizes a high-power laser and metal powder along with a closed-loop feedback system. Multi-axis in combination with DMD, gives the capability to build large-scale parts with more aggressive curvatures and higher complexities. This presentation will highlight the rationale behind the process of decomposing 3D-printed parts for multi axis buildup. It will also cover strategies for tool pathing and positioning parts for deposition process. Additionally included will be the benefits of multi-axis with DMD, such as reducing or eliminating supports, more flexibility with multi-material parts, and saving material and build time. There will be further information on the challenges such as distortion and how compensation can come into play, along with a couple of case studies to illustrate the decomposition method for 3D printing parts with multi-axis. Examples of the various applications of multi-axis 3D printing, including satellite oxidizer tanks, hydraulic system components, and more will be discussed. Finally, the benefits of using DED for manufacturing of large scale complex parts.

106 - Identifying, Quantifying, and Determining the Root Causes of Specific Spreadability Issues with AM Powders
Gregory Martiska, Mercury Scientific Inc.

Powders used in the AM industry either spread well or they do not. Poor powder spreading is due to specific issues with the powder or printer parameters. Therefore, the specific spreadability issues must be identified and quantified so that the root cause of the issue can be determined and corrected. Data will be presented in identifying and quantifying various spreadability issues including low layer density, low layer thickness, non-uniform layer coverage, channeling, and layer waviness. The root causes of these issues are determined and corrective action are presented. 

034 - Moisture in Metal Powders: How to Track Properties Drift During Storage?
Aurélien Neveu, Granutools

Metal powders feedstock is an important part of powder bed based Additive Manufacturing (AM) processes. The quality of the build parts is highly dependent on the powder bed homogeneity and density which are directly related to the powder properties. However, feedstock batch properties can evolve due to powder production variability, storage, aging or successive recycling. Especially, moisture can induce oxidation that leads to an alteration of the chemical properties of the particles and subsequent modification of particle/particle interactions. A better understanding of the influence of moisture on metal powder behavior is thus essential to reduce feedstock variabilities due to property drift during storage. In this study, the influence of short and long-term exposure to humid air on several metal powders is investigated. In order to track small variations of powder properties, an improved tapped density analyzer is used to provide high accuracy and repeatability of the measurements.

 

Special Interest Program Abstracts

 

 

SIP-6-1   Strategies for Sustainability

 

512 - Aspects of Critical Minerals and Sustainability That Will Impact the Powder Metallurgy Industry
Ian Donaldson, FAPMI, GKN Sinter Metals

The automotive industry has been facing disruption as it transforms to clean energy to address the environmental impacts that are leading to global climate change. In the transition to clean energy, critical minerals bring new challenges. For example, a typical electric car requires six times the mineral inputs of a conventional car. Batteries, EV motors and electrical networks associated with clean energy will require an enormous amount of minerals such as nickel, copper and aluminum with copper being a foundation for all technologies related to electricity. This shift to clean energy with the fast-growing demand for these non-renewable minerals makes sustainability efforts more challenging. Sustainability, which can be defined as the ability to meet existing needs without impeding future generations from meeting their needs, has become an emphasis as industries strive to improve the environmental performance of their organizations. This presentation delves into these issues and how they impact the powder metals industry.

506 - Opportunities for Life-Cycle CO2 Reduction for Additively Manufactured Parts
Jordan Tiarks, Ames Laboratory

Development of additive manufacturing {AM) technologies has upended traditional manufacturing and supply chain systems and has provided opportunities for redefining labor requirements, materials selection criteria, component design principles, and has provided accelerated product development opportunities due to rapid prototyping and design. However, evaluating the life-cycle cost benefits and energy and environmental impact of an AM part vs a traditional manufactured part remains a challenge. An accurate cost-benefit analysis is difficult to establish, often leading to hesitation in adopting AM or the pursuit of AM for the wrong applications. This presentation will outline key impact criteria in the context of a generic AM part lifecycle analysis, highlighting opportunities for greenhouse gas emissions reduction. Supported by USDOE-EERE-AMO through Ames Lab Contract DE-AC02-07CH11358.

511 - Sustainability - Making a Difference with Metal Powders
Jacob Maruschok, North American Höganäs Co.

Our prosperity - and that of our customers - depends on society and the natural environment being healthy. However, challenges such as population growth, resource scarcity, climate change and social inequality threaten this health. That's why Hoganas has made a deep commitment to sustainability and aim to become the sustainability benchmark within the steel industry. Hoganas has committed to net-zero carbon dioxide emissions by 2045, with an interim target of 30% reduction by 2026 relative to 2018. During 2021, Hoganas has run a competence building site-by-site process to identify CO2 emission reduction opportunities. The result identified activities corresponding to 86% reduction of our scope 1 and 2 emissions to 2045, and an estimated 30% reduction of scope 3 emissions from raw materials. The main opportunities are a transition to fossil free electricity, from fossil fuels to biofuels and electrification. Our objective is to be able to offer products with significantly lowered carbon footprint to the market within the near future.

 

 

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