045 - High-Throughput Materials by Design Framework Utilizing Experimental and Computational Tools
Sean Fudger, U.S. Army Research Laboratory
Traditional material discovery and development follows an Edisonian approach of trial and error yielding few significant improvements at intermittent intervals. The purpose of this research is to utilize machine learning (ML) to help guide the material development process, particularly focusing on using computational techniques to explore complex multifactorial experiments in addition to data collection and analysis. We will demonstrate high-throughput material science concepts applied to development of complex concentrated alloys (CCAs). By harnessing computational modeling and automating processes, material discovery, synthesis, characterization, and testing can be rapidly accelerated.
070 - Development of Localized Laser Preheating of AA6061 Powder as a Selective Laser Melting Technique to Improve Mechanical Properties of 3D Printed Parts
Conner Larocque, Lehigh University
AA6xxx series aluminum alloys have long been used in industrial applications for their high strength-to-weight ratio, weldability, and relatively low cost. While there is industrial interest in additive manufacturing (AM) of high-strength aluminum alloys, the process comes with several technical challenges stemming from AA6xxx series material properties. While some selective laser melting (SLM) machines are equipped with heated powder systems, many do not operate at optimal temperatures for aluminum alloys. The research aims to develop novel methods of reducing thermal gradients in selective laser melting of AA6061 via localized laser preheating of the powder bed to limit micro crack formation. Local laser preheating consists of sequential low-energy passes to add heat to desired areas. The effectiveness of this process and its contribution to the AM process were then evaluated through microstructure analysis as well as mechanical testing.
134 - Copper Heat Sinks: Design and Fabrication via Sinter Based Material Extrusion (MEX) 3D Printing
Kameswara Pavan Kumar Ajjarapu
Copper heat sinks, especially for electronic applications, are typically manufactured using conventional techniques such as bonding, forging, folding, skiving, or machining. Such heat sinks tend to have simple fin/pin structures, partly attributed to the limitations of conventional processing technologies. In this work, we utilize topology optimization to overcome challenges in transforming decade-old traditional sink of heat design using the sinter-based material extrusion (MEX) 3D printing process. In this work, we developed a >90wt.% copper powder-filled polymer filaments to fabricate thermally efficient heat sink designs that were MEX 3D printed and subsequently processed to remove polymer (debinding) and sintered to achieve dense copper parts. It was identified that thick and thin features in heat sinks tend to debound at different rates due to the differences in surface area and amount of binder material that needs to be removed. Although this differential behavior poses challenges with retaining part integrity post debinding and sintering, it can be overcome using techniques such as topology optimization. Therefore, this study looks at understanding the structure-material property relationships behind 3D printing copper heat sinks by MEX-3D printing process by implementing topology-optimized designs that were tested for their thermal efficiency using simulation and experiments.
135 - On the Effect of Building Platform Material on Laser-Powder Bed Fusion of a Ni-Base Superalloy HAYNES® 282®V
Abdul Shaafi Shaikh, EOS Finland
Additive manufacturing (AM) by laser powder bed fusion (LPBF) involves melting of layers of powder onto a substrate, called a building platform. Due to cost or convenience considerations, building platform materials rarely match the LPBF material, especially for high temperature materials. To ensure tolerances in component geometries, AM components are often stress-relieved / heat-treated while still attached to the building platform. It is therefore important to understand the effect of dissimilar building platform materials on properties of the built-up material. These effects may be particularly important for high performance materials such as Ni-base superalloys used for critical applications in the aerospace and energy industries. To investigate this effect, samples of a Ni-base superalloy HAYNES® 282® were built onto a carbon steel building platform in several configurations. The samples were removed from the building platform after heat treatment and subjected to detailed composition analysis and microstructural characterization to investigate the effect of the building platform material on the properties of the additively manufactured part. Room temperature and high temperature tensile testing were used to characterize the material. Results showed no risk of large-scale chemical composition change, or mechanical property degradation of built-up material from on-platform heat treatment.
145 - Binder Jet Printing of Ti-6-Al-4V with Ultra-Fine Microstructure
Nathan Jump, University of Utah
Binder Jet Printing (BJP) has recently emerged as a feasible manufacturing method for small to large scale parts, but currently, the full capabilities of this technology have some restrictions. Titanium is one of the most desirable materials used in manufacturing due to its high specific strength, high ductility, corrosion resistance, and biocompatibility, yet at this time, titanium still presents a plethora of difficulties that impede its scaled production via BJP. Many of these difficulties are rooted in the fact that powder metallurgy (PM) Ti parts often have too coarse of a microstructure to compete with its wrought counterpart. Therefore, by integrating the Hydrogen Sintering and Phase Transformation (HSPT) process into BJP there is an opportunity to produce relatively low-cost PM Ti parts with comparable strength and ductility. The following research is a summary of the integration of HSPT with BJP along with the improvements provided by hot isostatic pressing (HIP).
901 - The Effects of Sintering Conditions on the Explosion of CW0350 Parts
Julie Hedlund, Penn State DuBois
Powdered metal parts molded from CW0350 mix were observed to explode during the sintering process. This, in turn, has caused a high scrap/material waste during production. This study was conducted to determine the root cause in order to reduce the amount of scrap created from exploding parts by at least 2%. Part samples were tested at different furnace conditions (sintering temperature, atmosphere, and belt speed) and then compared to a controlled sample ran at typical router specifications. When the results of the tests were compared to the standard, the samples that ran with an increase of 50CF hydrogen, a 50°C increase in temperature, or a 1.0 inch/min slower belt speed showed the highest percentage of success. These tests yielded zero exploded parts during their run which reduced the fall out percentage from an average of 6% to 0%.
903 - Characterization and Validation Experiments for a Binder Jet 3D Printing Modeling Framework
Wesley Combs, Rice University
Binder Jet 3D Printing (BJ3DP) is a form of additive manufacturing that utilizes a polymeric aqueous-based solution to bind powder particles into primitives which layer-by-layer compose “green parts”. The Particle Flow and Tribology Lab can simulate this process and is interested in understanding what jetting phase parameters (nozzle translation speed, jetting frequency, particle size) affect important green part qualities (saturation, primitive morphology, green part strength). My project focused on creating a robust experimental validation rig to substantiate our lab’s simulated results while designing and 3D printing a fixed-funnel configuration to measure the angle of repose (AoR) of nickel alloy powders of various particle sizes, an important simulation input parameter. I constructed a BJ3DP assembly including a powder bed structure and printhead holder with a graphical user interface for actuation and control. I also built a fixed-funnel AoR test configuration. Both assemblies garner invaluable experimental results that matched well with simulations.
904 - Finite Element Modeling of Aluminum Alloy Sintering of Metal Binder Jetting Parts
Nicholas Queiroz Avedissian, Ohio State University
Metal Binder Jetting (MBJ) additive manufacturing (AM) has been expanding its industrial applications due to high production rates when compared to other AM processes. A key challenge with MBJ is that the as-printed part is not fully dense and requires sintering after printing. The parts can incur significant shrinkage and distortion during sintering. In the literature, extensive work has been done in numerical modeling of stainless steel sintering. However, aluminum alloy, another important structural metal, presents a significant difference as the sintering is done above the solidus temperature (also called liquid phase sintering). There is limited knowledge on material behaviors such as grain growth kinetics, and viscous- or creep-like deformation at those high temperatures. In this work, literature on aluminum alloy sintering was critically reviewed and then utilized in an existing elastic-viscoplastic continuum model. The effect of sintering parameters on shrinkage and distortion was computed and validated against literature data.
905 - Modeling Air Pressure Development in Compacted Powders
Joseph Wright, Drexel University
Entrapped air within powder compacts has the potential to develop defects for materials with weak cohesion, reduce the overall compact strength even when an observable defect is not formed. Recently computational methods have been proposed to model the air pressure gradient developed throughout the particulate compact. To complement prior modeling work, we built a specially developed apparatus that measures the volume of air expelled during compaction and can be used to validate estimates of the internal air pressure distributions and to provide an estimate of the powder permeability, which is necessary for the calibration of the model. This work also provides realistic estimates of the internal stress conditions within the compact and can be the basis for the prediction of strength reduction due to the presence of the entrapped air.
906 - Cold Sintering of Iron Powders for Use in SMCs Using Copper Ferrite Surface Modification
Linsea Foster, Penn State DuBois
Cold sintering of metals is explored using aqueous chemistry and heated compaction. Various surface modification methods have been used for studying cold sintering techniques. The application of surface modified particles in warm compaction has shown enhanced strength properties through various mechanisms. Here we explore use of copper ferrite coatings to enhance the strength and magnetic properties of iron for use in soft magnetics composites. The challenge with SMCs is producing a material that is both electrically insulating and exhibits adequate strength. By applying an electrically insulating layer, such as copper ferrite, and applying cold sintering technique, it is expected that both relatively high electrical insulation and strength may be achieved. The greater the electrical insulation, the more magnetically efficient it can operate in electric motors. The size requirements for producing SMCs will be dependent on its efficiency, so producing magnetically efficient motors is prudent to producing lightweight electric motors.
907 - Increasing Part Density and Strength in Metal Binder Jetting Through Lattice Infill Patterning
Amanda Wei, Virginia Tech
Use of a liquid binding agent is critical for forming part shape and providing green part strength in metal binder jet (BJ) additive manufacturing (AM). Traditionally, binder is homogeneously deposited throughout the entire part cross-section during printing. However, recent research suggests that reducing the quantity of binder present through a shelled part design increases sintered part density over that of the conventional solid binder infill. Consideration of the reduction in green part properties as a result of reduced binder usage should be explored as well. In the present work, a binder patterning strategy comprised of a contour shell with various internal lattice or TPMS infill patterns are applied to 316L stainless steel powder to balance the tradeoff between green and sintered part properties. In particular, an octet infill was found to have 14% of the green part strength of a traditional solid infill, but a 36% higher sintered flexural strength.
908 - Additive Manufacturing of FeCrAlY Open Porous Structure Using Si3N4 as a Foaming Agent.
Sakineh Abbasi, Oregon State University
The aim of this study is the additive manufacturing (AM) of 316L stainless steel open porous structure to play the role of catalytic substrate for bioconversion applications. For such applications, the 3D morphology, and in particular the surface area, will strongly determine the performance. This study used a novel foaming agent, Si3N4, to produce interconnected pores made by laser powder bed fusion (LPBF). Unlike classical functional design for AM, the open pores considered in this study are the result of fabrication parameters (e.g. scanning laser speed) and not from a CAD design. This work shows that the scanning strategy and process parameters have a major influence on the resulting surface area and volume of open porous structures. Therefore, the presented findings may pave the way to add a higher level of functionality to the additive manufacturing of porous metal samples.
912 - Process-Structure-Property Relationships of Stainless Steel 316L DED Specimens
Matthew Engquist, California State University, Los Angeles
Directed Energy Deposition (DED) is a metal additive manufacturing technique that offers much higher deposition rates than Powder Bed Fusion (PBF) style methods. It accomplishes this partly by incorporating much larger melt pool sizes when depositing material. This increase in melt pool size results in a solidification rates and temperature gradients which results in a unique microstructure and associated mechanical properties. This study investigates the microstructure and properties of 316L austenitic stainless steel produced by the wire laser DED process on a Meltio M450 system. The end goal is to elucidate the process-structure-property relationship of this technique as it shows promise in rapid manufacturing for aerospace.
914 - Heat Treatment and Microstructure Evolution of LPBF Fabricated Ti-6Al-4V
Tristan Armstrong, University of Utah
LPBF is a frontier for the time-efficient and precise manufacturing of geometrically complex parts for a wide range of industries. LPBF fabricated parts have unique microstructures that differ significantly from the microstructure of wrought parts. Understanding how heat treatment parameters influence the microstructure of LPBF fabricated parts is a critical step toward achieving comparable or even superior mechanical properties to wrought parts. Presented is a qualitative analysis of the microstructural evolution of LPBF fabricated parts subjected to heat treatments of varying temperature.
918 - Comparative Analysis of Ultrasonic- and Gas-Atomized Al Feedstock Powders by X-Ray Microscopy and Automated Classification
Daniel Sinclair, Purdue University
In the laser powder bed fusion (LPBF) of metallic parts, powder morphology can negatively impact powder bed consistency and, subsequently, defect formation. Powder production processes vary in their ability to optimize morphology and size, leading to questions of quality control in LPBF manufacturing. Ultrasonic atomization, which forms droplets from a vibrating liquid, is compared to gas atomization, which vaporizes a molten stream. AlSi10Mg powders made with both methods were visualized using lab-scale X-ray microscopy. A set of dimensionless shape factors were collected for over 4,000 particles, and machine learning was trained to automatically apply a user-defined classification scheme based on features of interest. In the ultrasonic powder, overall sphericity was increased but coincided with an increase in pore size. This work additionally outlines a minimally intensive workflow based on automated measurement techniques and a classification method that can be trained on disparate particle species, ultimately reducing human input.
919 - Synthesis Refinement of Al/Ca PM-DMMCs for Overhead Conductors
Dustin Hickman, Iowa State University
A unique synthesis of low-temperature solid-state consolidation of Al and metallic Ca utilizing a powder metallurgy (PM) route are being explored for use in developing high-voltage DC overhead transmission conductors. To increase the extrudability without utilizing a sealed can material, densification was explored utilizing 12-21ksi pressure and temperatures up to 180C without transforming metallic Ca to hard Al/Ca intermetallics for subsequent consolidation and deformations. Wire samples with three levels of deformation true strain were synthesized and characterized through this PM route. These single wires retained competitive, repeatable material properties compared to commercially available overhead conductors with potential for even greater strengths. The results presented serve as a proof of concept for achieving greater strengths from simply decreasing the Ca powder size distribution utilized for the Al/Ca wire synthesis whilst minimally affecting electrical conductivity. Funding from DOE-OE through DE-AC02-07CH11358.
921 - SS316L and 17-4 PH Bimetallic Structures Using Powder-Based Laser-Directed Energy Deposition
Aruntapan Dash, Washington State University
The present research is focused on developing novel bimetallic structures of 17-4 PH and SS316L stainless steels. SS316L powders with particle size 53-150 µm and 17-4 PH powders with particle sizes 15-53 µm are used as feedstock material in a powder-based L-DED metal AM system (FormAlloy, Spring Valley, CA) for printing the samples. Five different compositions, including single and multilayer bimetallic structures, were printed using the feedstock materials with optimized process parameters for each. The printed bimetallic structures have not shown any macro defects. Printed samples were subjected to phase and microstructure characterization. Primarily austenite (γ) and martensite (α) phases are observed in the printed samples. Microstructural analysis revealed the formation of columnar, cellular, and equiaxed dendrites in the SS316L and martensitic structure in 17-4PH. Microhardness and compression tests were performed with these samples to understand how the layering sequence controls the deformation behavior.
923 - Optimizing Selective Laser Melting AM Parameters for Printing Thin-Walled Structures for Pressurized Applications
Peyton Archibald, California Polytechnic State University, San Luis Obispo
Selective Laser Melting (SLM) is a widely used additive manufacturing technology that offers great potential for producing complex geometries and functional parts. However, the optimization of printing parameters for thin wall parts that can withstand pressurized applications and ensure leak-free performance remains a challenging task. This study aims to optimize the printing parameters of an SLM 3D printer to produce thin wall parts for pressurized applications with improved leak-free performance. The printing parameters were systematically varied and their effects on the part's wall thickness, surface quality, and leak-tightness were analyzed. So far, the results show that optimizing the scan strategy of the laser is crucial in creating functioning, leak-tight parts. This study aims to provides valuable insights for optimizing the printing parameters of an SLM 3D printer to produce thin wall parts suitable for pressurized applications.
925 - Properties of Green and Sintered FC-0208 Using HGS 2.0
Cole Bressler, Penn State DuBois
Improved green strength and lower ejection forces means less broken green parts as well as the ability to machine green parts, reducing the wear on tooling. With the use of High Green Strength Second Edition (HGS 2.0) lubricant these desired properties could be achieved. A new proprietary lubricant, HGS 2.0, is being tested to determine its properties when used in the powdered metal process. This research is presenting the properties of HGS 2.0 lubricant as well as green and sintered parts of FC-0208, 316 stainless steel, and 304 stainless steel blended with this new lubricant. The FC-0208 samples were pressed to densities of 6.8g/cc, 7.0g/cc, and 7.2g/cc. The stainless-steel samples were pressed to densities of 6.3g/cc. 6.4g/cc, 6.5g/cc, and 6.6g/cc.
926 - Construction of a Customized Inkjet 3D Printer
Andrew Gillespie, Indiana University-Purdue University Indianapolis
In this work, the construction of an open-source inkjet printer. This printer utilizes a layer-by-layer droplet interaction and heat to help bond particles with the potential for ceramic and electrical components fabrication. The project's focus is on developing 3D printing of a component efficiently. The primary feedstock used in this procedure is powdered, granulated sugar with a mix of alcohol and food coloring to act as a bonding agent. The project demonstrates the efficiency and limitations of inkjet printing and the printing materials used. On-going experiments include improving the printer head, powder, and binder recipes, allowing us to find an efficient and cost-saving additive Manufacturing ceramic 3D printing technique.
927 - Using Simulation as a Supplemental Resource for Minimizing Sintering Distortion of BJP Parts
Nicholas Engstrom, University of Utah
Binder Jet Printing (BJP) of titanium is a promising additive manufacturing method for producing parts with high surface detail and physical properties. However, sintering can cause distortion and non-uniform shrinkage. Empirically optimizing part design and sintering parameters for each individual part is impractical. Simulation software can supplement the process to minimize sintering distortion by predicting shape change during sintering based on known titanium properties. This allows for part modification prior to sintering, with the prediction being confirmed through experimentation. This method builds on itself, which leads to further refinement of the simulation parameters for titanium for each iteration. This approach enables engineers to make informed decisions when designing titanium parts for BJP, leading to a more generalizable approach to minimizing sintering distortion.
929 - The Impact of Various Post-Processing Techniques on the Flexural Bending Fatigue Life of Additively Manufactured Aerospace-Grade Titanium Alloy (Ti-6Al-4V) Parts
Cristian Banuelos, University of Texas at El Paso
The aim of this project is to assess the effects of different surface finishing techniques of additively manufactured metal parts with relation to their fatigue life as they undergo bending loading. Laser powder-bed fusion technology was used to manufacture aerospace grade titanium alloy (Ti-6Al-4V) parts under standard manufacturing conditions. The parts were heat treated for stress relief and were then randomly assigned to the different surface finishing procedures to achieve an optimal testing geometry and improve the surface finish. The surfaces of the specimens were given a quality inspection and roughness measurements were taken using optical and mechanical approaches prior to mechanical testing. The specimens were subjected to four-point bending fatigue testing until fracture and the data was used to generate S-N curves; the fracture surface was also analyzed to better understand the failure mechanisms and the end use performance of the material under the various surface finishes.
930 - Comparison of Surface Texture Analysis Methods for Additive Manufacturing Laser Powder Bed Fusion
Alex De La Cruz, University of Texas at El Paso
Powder particles contribute to the as-built surface textures produced by additive manufacturing technologies. These surfaces attain irregularities, one common feature that can be distinguished is unmelted particles, which cause an apparent increase in roughness, leading to subpar mechanical performance and efficiency. Roughness measurements depict how flat and smooth the surface is. While machining is commonly used to eliminate the high roughness from AM-produced components, its capabilities are still limited for complex geometries. Using Laser Powder Bed Fusion (L-PBF) machine, Ti-6Al-4V samples were printed by altering the speed and power of the laser generating different textures. The as-built surface performance was tested by conducting four-point bending tests. Three surface texture measurements were compared: X-ray tomography, microscopy, and profilometer. The study emphasizes comparing these techniques, aiding current research on establishing a method in which the surface texture can be measured concisely and recognizing the application, and comparing the measuring technologies.
931 - Process-Microstructure-Property Relationships in Laser Powder Bed Fusion of Non- Spherical Ti-6Al-4V Powder
Mohammadreza Asherloo, Illinois Institute of Technology
An investigation of process-microstructure-property relationships in Ti-6Al-4V parts processed using laser powder bed fusion of non-spherical powder showed full control over porosity
content, surface roughness, microstructure, texture, and hardness. Increasing laser scan speed from 400 mm/s to 1500 mm/s eliminated the keyhole porosities and enhanced relative density to ~99.8 %. Also, the surface roughness (Sa) decreased from 119 μm to 21.8 μm. Microstructural observations showed that the primary beta grains were refined, and their shape factor increased from ~2.5 to ~5. Additionally, the hardness reached a maximum of 390 HV 0.5 when the scan speed was 1250 mm/s. An increase in laser power from 225 W to 370 W slightly changed the Sa between 16.2 - 21.43 μm. Additionally, the hardness increased from ~355 HV 0.5 to ~383 HV0.5 with increasing laser power. Synchrotron X-ray high speed imaging also showed the direct correlation between the melt pool depth and the texture intensity.
932 - Influence of Printer Design and Printing Parameters on Ballistic Ejection
Jacob Feldbauer, Penn State DuBois
Binder Jet Additive Manufacturing (BJAM) is a versatile powder bed technique that uses a binder deposited using ink jetting to form complex components. Ballistic ejection occurs during the application of the binder to the powder bed layer during the binder jet printing process. The momentum of the binder droplet impacting the powder bed results in a disturbance of the powder layer. This disturbance of the particles in each layer causes inconsistencies in the density and bonding during the sintering step of the process, resulting in a localized disruption in the uniformity of the materials properties.
The printer design and the parameters used to print influence the size and momentum of the binder droplet. The influence of these parameters will be reviewed to minimize ballistic ejection during printing and improve the quality and uniformity of the printed components. We use X-Ray computed tomography to study the differences in 17-4 steel parts as printed in the green state. This information will be critical for understanding the evolution of inhomogeneity in sintered components and their role in material properties.
936 - Development of a Novel Multi-Laser Scan Strategy to Reduce Micro-Cracking in Additively Manufactured Tungsten
Emmaline Hutchison, Ohio State University
Additive Manufacturing (AM) has seen a substantial rise in popularity over the past decade due to its increase in design freedom, the reduction in product development time, and its ability to address supply chain gaps. However, certain materials present issues when it comes to AM due to their unique material properties and laser powder bed fusion’s (L-PBF) inherent laser welding processes. Tungsten is one such material: it is difficult to machine and often cracks as it sheds the heat from L-PBF builds. This study examines the effects of a multi-laser melting and cooling processes on the material properties of tungsten parts. Metallographic analysis of printed samples was conducted to track the density across the builds. The use of a leading laser was observed to significantly contribute to the increased density of samples when compared to single laser builds.
938 - Application of Additive Manufacturing to Deliver Incremental Production of Conventional Powder Metal Components Without Compaction Tooling
Hope Spuck, Penn State DuBois
The conventional powder metal industry has always struggled with distributing the cost of compaction tooling and the need to maintain a competitive price of the final product. The result has historically limited the order size to high volume orders.
Although additive manufacturing of metal components has become more accepted. Additive techniques, such as laser powder bed fusion and traditional binder jet printing, have been focused on the production of small spherical particle sizes and materials that are less susceptible to oxidation, like 316 and 17-4. This has prevented the application of AM as a low volume process to complement the conventional press and sinter production of traditional powder metal chemistries and parts.
Recently, a new approach to additive manufacturing has provided a technique for the printing of conventional powder metal chemistries and particle size distributions. Using an FC-0208 powder, the physical properties and processing requirements will be reviewed to assess the application of this printing technique to expand the market for conventional press and sintering manufacturing.
940 - Additive Manufacturing of Aluminum Alloy by Metal Fused Filament Fabrication (MF3)
Sihan Zhang, University of Louisville
This research investigated additive manufacturing of Al-6061 aluminum alloy via metal-fused filament fabrication (MF3). This work focused on using the MF3 process to fabricate Al-6061 test coupons and optimize the MF3 process parameters to obtain improved mechanical properties. Feedstock with 57 vol.% solids loading Al-6061 was prepared by mixing Al-6061 powders and a polymer binder, followed by extrusion to fabricate a filament with a 1.75 mm diameter. The 57 vol.% Al-6061 powder-polymer filament was used to print green tablets and tensile bars with a Prusa MK3S+ 3D printer. Experiments were designed to optimize the 3D printing process parameters to obtain parts with the highest green densities. The green parts were subjected to solvent debinding, thermal debinding, and, finally, sintering processes to remove polymer content and become dense Al-6061 tablets and tensile bars. The sintered parts were characterized for grain structure, sintered density, and mechanical properties, and their prosperities were compared to metal injection molded (MIM) specimens. This work aims to enable rapid, predictable, reproducible, low-cost, and accurate production of metal parts with 3D features, thereby significantly expanding the current additive manufacturing capability.
941 - Machine Learning in Powdered Metallurgy
Cole Walker, University of Utah
There are many areas in powder metallurgy that can benefit from the implementation of machine learning. One of these areas is the determination of particle size, which can be done in multiple ways, but a highly accurate technique is using image analysis. Extracting the size from images can be time-intensive, and using machine learning to identify overlapped particles and accurately extract results can be extremely useful and efficient. Other applications of machine learning in powder metallurgy include investigating different material possibilities and optimizing powder synthesis and production processes. These applications are discussed, including their ease of implementation, scalability, accuracy, and potential.
947 - Development of Localized Laser Preheating of AA6061 Powder as a Selective Laser Melting Technique to Improve Mechanical Properties of 3D Printed Parts
Conner Larocque, Lehigh University
AA6xxx series aluminum alloys have long been used in industrial applications for their high strength-to-weight ratio, weldability, and relatively low cost. While there is industrial interest in additive manufacturing (AM) of high-strength aluminum alloys, the process comes with several technical challenges stemming from AA6xxx series material properties. While some selective laser melting (SLM) machines are equipped with heated powder systems, many do not operate at optimal temperatures for aluminum alloys. The research aims to develop novel methods of reducing thermal gradients in selective laser melting of AA6061 via localized laser preheating of the powder bed to limit micro crack formation. Local laser preheating consists of sequential low-energy passes to add heat to desired areas. The effectiveness of this process and its contribution to the AM process were then evaluated through microstructure analysis as well as mechanical testing.
948 - Spherical Ti-6Al-4V Alloy Powder Made by the Direct Reduction and Alloying (DRA) Process
MD Emran Hossain, University of Utah
Spherical Ti-6Al-4V alloy powder is one of the most demanding feed materials for additive manufacturing to produce near-net-shaped products. Atomization is the most used technique today to produce Ti-6Al-4V spherical powder, but high production cost drives the emergence of low-cost processes. Some new methods have been developed to produce spherical Ti-6Al-4V alloy powder; however, no process has been claimed to make it directly from raw oxides. This research demonstrates a novel pathway to make spherical Ti-6Al-4V alloy powder directly from basic oxides by hydrogen-assisted magnesiothermic reduction (HAMR). Raw metal oxides are mixed uniformly and reduced to form fine Ti-6Al-4V alloy powder, which is then granulated-sintered and deoxygenated (GSD) to produce the spherical powder. The process is called the direct reduction and alloying (DRA) process. Spherical Ti-6Al-4V alloy powders produced by this process have low interstitial impurities, controlled particle size distribution, uniform and homogeneous composition, and excellent flowability.
949 - Post-Processing Effects on Mechanical and Corrosion Behavior of Additively Manufactured 7050-Based High Strength Aluminum Alloy
Rupesh Rajendran, Georgia Institute of Technology
Additively manufactured(AM) high strength aluminum alloys are highly attractive to the aerospace industry due to inherent benefits of the AM process in addition to the alloy benefits such as high strength to weight ratio, corrosion, and fatigue resistant properties. Recent addition of inoculants or nanoparticles have reduced solidification defects in high strength aluminum alloys which was a bottleneck for adoption of these alloys. This work is focused on understanding the effect of post-processing treatments such as stress relieving, hot isostatic pressing(HIP), and solutionizing and aging on the mechanical and corrosion behavior of a 7050-based high strength aluminum alloy. Extensive characterization and mechanical tests are done to understand the effect of post-processing treatments. The result of this work is beneficial for optimization of post-processing treatments for target mechanical and corrosion performance. An equivalent wrought alloy is compared for understanding the differences and similarities between additive vs. wrought alloys for targeted application.
950 - Development of a Rapid Testing Method for Metal Additive Manufacturing
Keita Shimanuki, California Polytechnic State University, San Luis Obispo
Due to its infancy in industrial application, metal additive manufacturing process development is a vital area of research to produce high quality parts and increase production rate. Tensile and fatigue tests have been the dominant testing methods for qualification of process parameters. However, the amount of time and cost required to gain statistically significant data, especially when dealing with hundreds of different process parameter permutations, is an obstacle. Development of a go/no-go test method designed as a first pass filter for process parameters will increase efficiency in the development stage.
This experiment will utilize a drop weight impact test method, which is a mechanical test where a qualitative result, such as crack propagation or complete failure, can be obtained from the impact. To better resemble the dynamic nature of the impact test, a high strain rate tensile test will be used as a reference to find any correlation.
954 - Binder Jet Printing of Ti-6Al-4V with Ultra-Fine Microstructure
Nathan Jump, University of Utah
Binder Jet Printing (BJP) has recently emerged as a feasible manufacturing method for small to large scale parts, but currently, the full capabilities of this technology have some restrictions. Titanium is one of the most desirable materials used in manufacturing due to its high specific strength, high ductility, corrosion resistance, and biocompatibility, yet at this time, titanium still presents a plethora of difficulties that impede its scaled production via BJP. Many of these difficulties are rooted in the fact that powder metallurgy (PM) Ti parts often have too coarse of a microstructure to compete with its wrought counterpart. Therefore, by integrating the Hydrogen Sintering and Phase Transformation (HSPT) process into BJP there is an opportunity to produce relatively low-cost PM Ti parts with comparable strength and ductility. The following research is a summary of the integration of HSPT with BJP along with the improvements provided by hot isostatic pressing (HIP).
955 - Optimizing Repairs of Aluminum 7075 via Directed-Energy Deposition
Dylan Treaster, Penn State DuBois
Aluminum 7075 is a precipitation hardening alloy known for its high strength to weight ratio desirable ductility, and fatigue properties making it an alloy of choice for many critical applications. However, components built of Al7075 are often subjected to harsh environments over their service life ultimately leading to corrosion, and consequently the need for repair. Repairing Al 7075 is often unattainable via traditional arc-based welding techniques. Weld repairs exposes the material to high temperatures which in turn produces elemental segregation that leads to liquation and solidification cracking which is attributed to low-melting point alloying elements such as zinc and magnesium. This study focuses on the repair of Al 7075 via laser-based directed energy deposition, additive manufacturing. Laser-based directed energy deposition has the ability to control the energy source by tailoring the laser spot size, power, and process mode (continuous wave or pulsed wave) along with the ability to employ various feedstock which allows for process optimization to alleviate cracking thereby making repair fabrication viable. Parameter development and process optimization were conducted to decrease the material debit in the base structure and provide a quality repair.
960 - Project MANTLES
Darren Takaoka, Ohio State University
NOTE: Pending Approval for Public Release.
The MANTLES project is an ongoing partnership between NCDMM, Ohio State University's Center for Design and Manufacturing Excellence, industry Partners including Hexagon 3D, Collin's Aerospace, Northrop Grumman, Lockheed Martin and Ursa Major. The scope of the project was to create and optimize a workflow leveraging both Post Process Imaging and prebuild simulation to reduce distortions in Laser-Powder Bed Fusion Parts. This workflow is to be used to achieve smaller Geometric Tolerances in the Produced Parts. The Parts were Printed at CDME on an EOS M290 in Inconel powder, 3D Scanned by a Hexagon 3D laser Scanner. The geometries to be printed and analyzed was initially a Rocket nozzle with complex internal geometries supplied by Ursa Major but was later replaced by a less structurally stiff duct part drawn up at CDME to observe a greater initial distortion.