Additive Manufacturing: Materials Design and Alloy Development V – Design Fundamentals: Ferous Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Integrated Computational Materials Engineering Committee
Program Organizers: Behrang Poorganji, Morf3d; Hunter Martin, HRL Laboratories LLC; James Saal, Citrine Informatics; Jiadong Gong, Questek Innovations LLC; Orlando Rios, University of Tennessee; Atieh Moridi, Cornell University

Wednesday 8:30 AM
March 22, 2023
Room: 24C
Location: SDCC

Session Chair: Atieh Moridi, Cornell University


8:30 AM  
Effect of Carbon Content on the Microstructure and Mechanical Properties of Steels Additively Manufactured by Laser Powder Bed Fusion: Thinh Hyunh1; Nemanja Kljestan2; Abhishek Mehta1; Kevin Graydon1; Marko Knezevic2; Brandon McWilliams3; Kyu Cho3; Yongho Sohn1; 1University of Central Florida; 2University of New Hampshire; 3DEVCOM Army Research Laboratory
    Novel carbon-bearing steels were gas-atomized and used as powder feedstock to explore the feasibility of additive manufacturing by LPBF. Charge alloys were inductively melted at 1800°C under Argon shrouding and gas-atomized using Argon at a pressure of 2 MPa to produce low- and high-carbon bearing alloys. LPBF optimization was performed as a function of laser power and scan speed, and relative density higher than 99 % was achieved. Carbon-bearing alloys were compositionally modulated to produce austenite or martensite in the as-printed condition. The low carbon-bearing alloy contained 97% quenched martensite and 3% austenite, while the high carbon-bearing alloy contained 98% austenite and 2% martensite. Changes in the as-built microstructure were documented as a function of laser scan speed, while phase analyses were examined using electron microscopy and x-ray diffraction. The effect of C on the mechanical performance and solid-state phase transformation were elucidated via hardness and uniaxial tension tests.

8:50 AM  
Ultra-High Strength and Ductility in a Lightweight Fe-Mn-Al-C Austenitic Steel Fabricated via Laser Powder Bed Fusion: Raiyan Seede1; Jiahui Ye2; Austin Whitt3; Sean Gibbons4; Philip Flater4; Bernard Gaskey4; Alaa Elwany2; Raymundo Arroyave2; Ibrahim Karaman2; 1Lawrence Livermore National Laboratory; 2Texas A&M University; 3NASA Glenn Research Center; 4Air Force Research Laboratory
    Low-density Fe-Mn-Al-C steels have generated recent interest in the automotive and defense industries due to their potential for structural weight reduction while maintaining high strength and ductility. Austenitic Fe-Mn-Al-C steels with high Al content (~9 wt.%) exhibit strengths greater than 1.2 GPa with ~35% elongation. Laser powder bed fusion (LPBF) additive manufacturing (AM) can fabricate steel parts with complex geometries and has the potential to control local microstructural and mechanical properties. However, literature on LPBF processing of Fe-Mn-Al-C alloys has typically focused on low Al content (<5 wt.%) twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) compositional regimes. This study presents the effects of LPBF processing on an Fe-30Mn-9Al-1Si-0.5Mo-0.9C austenitic steel. A process optimization framework is utilized to determine an optimal LPBF processing window for fabrication of >99% density parts. As-fabricated specimens displayed significant work-hardening characteristics with excellent strength and ductility of up to 1.3 GPa and 36% elongation.

9:10 AM  
Manufacturing of MS1-P20 Hybrid Steels via Laser Powder Bed Fusion: Sajad Shakerin1; Mohsen Mohammadi1; 1Marine Additive Manufacturing Centre of Excellence (MAMCE)
    Hybrid steel was produced using maraging steel (MS1) and cold work tool steel (P20). The laser powder bed fusion (LPBF) technique was carried out to deposit MS1 powder on the P20 substrate plate. The as-built MS1-P20 hybrid steels were prepared for microstructural investigations. Scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and electron backscatter diffraction (EBSD) were performed to study the interfacial microstructure. The mechanical properties were evaluated using a microhardness test and a three-point bending test. The investigation showed that MS1 grains followed a non-epitaxial solidification on top of P20 grains, and a cohesive bonding was formed between MS1 and P20 sides. The deposited MS1 obtained higher hardness values than the P20 substrate. In the three-point bending condition, the interface and MS1 side exhibited strong behavior, however, the P20 substrate was remarkably deformed and cracked under extreme tension stresses.

9:30 AM  
Unique Microstructure and Phase Transformation Pathway in an Additively Manufactured 316L-ceramic Composite: Mo-Rigen He1; Joesph Sopcisak2; Christopher Marvel3; Samuel Price4; Ian McCue4; Jason Trelewicz5; Steven Storck2; Kevin Hemker1; 1Johns Hopkins University; 2Johns Hopkins University Applied Physics Laboratory; 3Lehigh University; 4Northwestern University; 5Stony Brook University
    Rational control of phase constituents and their distribution is essential for the creation of metal matrix composites with synergistic properties. To this end, additive manufacturing (AM) often results in far-from-equilibrium microstructures that provide additional avenues for material design. In this study, a novel composite produced with selective laser melting of 316L stainless steel and entrained ceramic particles is characterized with comprehensive electron microscopy techniques. The ceramic particles are fully decomposed and transformed into continuous nanolayers composed of carbides and intermetallics at the intragranular cell walls in the 316L matrix. Close inspection of the reaction zone indicates that accelerated solute diffusion along the cell walls leads to the formation of this new microstructure. The pivotal role of AM processing in the phase transformation pathway is further rationalized with thermodynamic calculations. This study demonstrates reactive additive manufacturing as a rich processing space to fabricate metal-ceramic composites with unique microstructures and superior properties.

9:50 AM  
The Development of a Directed Energy Deposition (DED) Printability Framework for Improving Part Density and Performance in High Strength Martensitic Steels: Matthew Vaughan1; Michael Elverud1; Jiahui Ye1; Raiyan Seede1; Sean Gibbons2; Philip Flater2; Bernard Gaskey2; Alaa Elwany1; Raymundo Arroyave1; Ibrahim Karaman1; 1Texas A&M University; 2AFRL-EGLIN
    While the additive manufacturing (AM) directed energy deposition (DED) technology provides a novel and efficient method for printing high strength steels to novel geometries, its inherent complexity merits a need for the development of a systematic DED framework that quickly identifies the ideal printability space for a given steel, and subsequently enables one to print the material to full density and dimensional accuracy. Afterwards, achieving optimal strengthening in novel high strength martensitic steels via DED and the Hall-Petch effect would be much more straightforward. To address this need, the present study develops a DED printability framework, where an advanced high strength martensitic steel known as AF9628 is printed to full density, high strength, and respectable ductility (ρ > 99%, UTS > 1.2 GPa, εf > 10%). The introduced process optimization framework is easily adaptable to other high-end steels and alloys and should prove quite valuable to the AM research community.

10:10 AM Break

10:25 AM  
Design of a TRIP and TWIP Steel through Additive Manufacturing of Dissimilar Steels: Noah Sargent1; Samad Firdosy2; Xin Wang1; Richard Otis2; Jonathan Poplawsky3; Wei Xiong1; 1University of Pittsburgh; 2Jet Propulsion Laboratory, California Institute of Technology; 3Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    Functionally graded materials (FGMs) are manufactured using the directed energy deposition (DED) process through a dynamic variation of composition in consecutive deposited layers. In addition to the development of dissimilar material joints, FGMs research doubles as a high-throughput experimental methodology for alloy design. In this work, stainless steel 316L (SS316L) and high strength low alloy steel (HSLA) FGMs are manufactured using DED with the goal of designing a low Manganese TRIP & TWIP steel. Compression testing of as-built SS316L and HSLA FGM revealed evidence of TRIP & TWIP effects. Further tensile testing of the SS316L and HSLA alloy mixtures demonstrated the successful design of an as-built TRIP and TWIP steel with an ultimate strength of 980 MPa and elongation of 26%. Experimental measurements of microsegregation are compared with CALPHAD modeling to evaluate the ability to predict the impact of microsegregation on phase stability and stacking fault energy in as-built steels.

10:45 AM  
Capturing the Effect of a Novel Inoculant on the Microstructure and Mechanical Properties in a Stainless Steel 316L Alloy Produced by Laser Powder Bed Fusion: Aakifa Farooq1; Sam Tammas-Williams2; Arunabhiram Chutia3; Nghia Vo4; Peter Lee5; Mohammed Azeem1; Peter Lee6; Mohammed Azeem6; 1University of Leicester; 2The University of Edinburgh; 3University of Lincoln; 4National Synchrotron Light Source II; 5Harwell; 6University College London
    Corrosion resistance is crucial in the fast-evolving world of bespoke components produced by laser powder bed fusion melting (PBF). In case of high alloy Fe systems such as stainless steels (SS) it was initially thought that the PBF will help in grain refinement due to fast cooling rates. However, massive grains are observed in SS processed via PBF. Here we have identified a novel inoculant and a processing pathway to incorporate the inoculant in SS powders which are then used in PBF. Various inoculant weight fractions have been examined and their effect on microstructure and mechanical properties is assessed. Formation of defects is examined and quantified using X-ray CT. Extensive EBSD analysis has been performed and correlated with the CT data before and after mechanical deformation. The results demonstrate that the inoculant alters the solidification pathways which has a direct impact on the grain refinement in 316L stainless steel alloy.

11:05 AM  
Laser Powder Bed Fusion Processing of Mechanically Alloyed 4wt% TiC Nanoparticle Reinforced 316L Stainless Steel: Ryan Anderson1; Stephen Cooke1; Joseph Sims1; Madelyne Rushing1; Melissa Forton1; 1Quadrus Advanced Manufacturing
    Through a Small Business Innovation Research (SBIR) contract, Quadrus Advanced Manufacturing (QAM) investigated the effect of mechanically alloying 4wt% TiC nanoparticles into 316L stainless steel powder on the alloy’s as-built microstructure when processed via laser powder bed fusion (L-PBF). QAM used a planetary ball mill to coat the outside of the 316L powder with the TiC nanoparticles. The as-built microstructures of both the non-reinforced and reinforce 316L were compared. Additionally, QAM performed preliminary uniaxial tension testing and Rockwell hardness testing to examine the difference in each alloy’s mechanical properties. Lastly, representative samples from both alloys underwent EBSD analysis to better understand the differences in the grain structure and orientation responses seen in each alloy.

11:25 AM  
Effects of Oxygen Exposure and Powder Chemistry on Oxide Dispersion Strengthened Steels Printed with Gas Atomization Reaction Synthesis (GARS) Powders: Matthew deJong1; Sourabh Saptarshi1; Iver Anderson2; Christopher Rock1; Timothy Horn1; Djamel Kaoumi1; 1North Carolina State University; 2Ames Laboratory
    Oxide-Dispersion Strengthened steels are promising candidates for structural applications for different industries (nuclear, fossil energy) thanks to their outstanding mechanical properties at high temperatures and radiation resistance. This is due to the presence of a fine dispersion of nano-scale oxides distributed throughout the matrix. Such microstructure is traditionally processed via mechanical alloying of steel and yttria powders, followed by consolidation, and thermo-mechanical processing, making it a costful process. Steel powder based on 14YWT composition was produced via gas atomization reaction synthesis and consolidated via LPBF in argon atmospheres with varying amounts of oxygen in order to prevent these defects. The process was successful in producing the oxide dispersion in a steel matrix. Microscopy (TEM) characterization was conducted on FIB liftouts and XRD was performed on printed samples. The impact of oxygen exposure and powder chemistry on oxide size distribution, as well as phases present in the printed parts are discussed.

11:45 AM  Cancelled
Enhanced Magnetic Properties of Additive Manufactured Fe-Ni Permalloy through the Optimizing the Production Parameters: Farahnaz Haftlang1; Eun Seong Kim1; Hyoung Seop Kim1; 1Pohang University of Science and Technology
    The present study focused on improving the magnetic properties of in-situ synthesized Fe-Ni permalloy by engineering the microstructural characteristics and the predominant crystallographic texture. Fe-50%Ni samples with different production strategies were produced through the directed energy deposition method and subsequent heat treatment. Accordingly, by using the optimum production parameters, homogeneous distributions of Fe/Ni elements are achieved in all the experimented samples during the in-situ alloying process. This resulted in high magnetization saturation, Curie temperature, and relatively low coercivity. Applying post-DED heat treatment led to further improvement in the magnetic properties due to the reduction in the dislocation density of the as-print in-situ alloyed samples with no specific change in the microstructural characteristics. Therefore, using the two-step production approach consisting of laser in-situ alloying additive manufacturing and short-time heat-treatment would be considered an efficient route to enhance the magnetic performance of soft magnetic materials compared to the conventional process.