Additive Manufacturing: Materials Design and Alloy Development V – Design Fundamentals: Advanced 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
Thursday 2:00 PM
March 23, 2023
Room: 24C
Location: SDCC
Session Chair: Behrang Poorganji, Morf3D
2:00 PM Invited
Microstructure and Mechanical Properties of In-situ Nano Oxide Reinforced CrMnFeCoNi High Entropy Alloy Matrix Composite Manufactured by Laser Powder Bed Fusion: Kee-Ahn Lee1; Young-Kyun Kim2; 1Inha University; 2Korea Institute of Materials Science
CrMnFeCoNi high-entropy alloys (HEAs) exhibit an excellent combination of tensile strength and ductility. This study led to the suggestion of a new method for the development of high performance HEAs by jointly utilizing additive manufacturing (AM) and the addition of interstitial atoms. The interstitial oxygen present in the powder feedstock was transformed into beneficial nano-sized oxides during AM processing. The microstructure, tensile, impact toughness, fatigue, and cryogenic, and hydrogen charging mechanical properties of the in-situ nano oxide reinforced CrMnFeCoNi alloy matrix composite manufactured by laser powder bed fusion were investigated. The HEA nanocomposite represented superior yield strengths of 0.77 GPa and 1.15 GPa and tensile strengths of 0.92 GPa and 1.45 GPa at 298 K and 77 K. Charpy impact and fatigue results showed the impact energies of 176.2 J and the fatigue strength of 280 MPa. The deformation and fracture mechanisms of the HEA composite was also discussed.
2:30 PM
Expansion of Additive Manufacturing Capabilities into In-situ Alloying of Dispersion Strengthened, High Temperature Cu Alloys: David Scannapieco1; David Ellis2; John Lewandowski1; 1Case Western Reserve University; 2NASA Glenn Research Center
New alloys and materials are potentially possible through additive manufacturing’s unique thermal history. Current literature explores the fabrication of eutectic and solid solution strengthened alloys through in-situ alloying, to take advantage of AM’s unique thermal history. The resulting lessons learned by in-situ alloying currently available materials will likely lead to the development of novel materials solely possible through in-situ alloying. This work will expand the application of in-situ alloying via additive manufacturing to NASA’s GRCop-42 (Cu-4at% Cr-2at% Nb), a high temperature copper alloy which has shown success in additively manufactured combustion chambers from pre-alloyed powders. GRCop-42 is unique to literature because a reaction to form the Cr2Nb dispersoids is required during the in-situ alloying. Both reaction completion rate and how input energy from the AM process influences the reaction progress will be evaluated. Ultimately, expansion of in-situ alloying capabilities provides further insight to develop novel materials using AM.
2:50 PM
Development of a High Throughput Method to Assess the Suitability of New Metals for Additive Manufacturing: Daniel Porter1; Moataz Attallah1; 1University of Birmingham
Alloy development for additive manufacturing is relatively slow process due to the need to generate powders to assess the weldability and reactivity of the different materials. In-situ alloying requires optimisation of its parameters prior to assessing the processability of the alloy. In this study a powder metallurgy-based route was incorporated, using elemental powders which were blended, outgassed, and then HIPed. A laser track (bead on plate) was used to assess the processability of different materials. The reactivity of the material (known to influence the meltpool stability and the safety of the powder being studied) was determined using a plume analysis image processing technique that observed the vapour plume generated by the laser. Meltpool observations were performed to assess the cracking suscpetibility of the alloys. Hardness measurements were taken in and outside the meltpool itself. The cracking observations were correlated with solidification models.
3:10 PM
Evaluation of SLM Parameters for Producing Elementally Homogeneous Printed Products Using Novel Dry Metal Alloy (DMA) Powder Feedstock: Stephen Hanson1; Daniel Jacintho1; Janice Lucon1; Sudhakar Vadiraja1; 1Montana Technological University
A component of metal powder bed fusion technologies is the powder feedstock. Dry metal alloying (DMA) is a process that involves mixing elemental and/or ferro-alloy powders (e.g., iron with ferrochromium, ferromanganese, etc.) in an acoustic mixer to achieve bulk mixed powder composition matching the desired alloy. DMA allows a high level of flexibility – permitting alloys tailored to the requirements of service. Optimization of print parameters while using DMA during selective laser melting (SLM) is underway. Short melt pool residence times in SLM present challenges in achieving compositional homogeneity. Updates related to improving deposit characteristics for 304L stainless steel will be discussed. Characterization analysis will be presented, including optical microscopy, scanning electron microscopy, elemental mapping, and bulk composition analyses. Improvements on compositional homogeneity while using DMA during SLM will be reported.
3:30 PM Break
3:45 PM
Oxide Coarsening Effects during Melt-based Additive Manufacturing -- Physics-based Modeling: Roger Hou1; Timothy Stubbs2; Aijun Huang2; Zachary Cordero1; 1Massachusetts Institute of Technology; 2Monash University
Oxide dispersion-strengthened (ODS) superalloys incorporate nano-scale oxide dispersoids that inhibit dislocation motion, imparting exceptional high temperature creep resistance for the most demanding structural applications. There is current interest in using metal additive manufacturing (AM) techniques, e.g., laser powder bed fusion (LPBF), to directly form net-shaped ODS components. However, a major concern with AM of ODS alloys is that the dispersoids will coarsen, agglomerate, and lose their efficacy during the brief melt cycle. Here we present a physics-based model of such coarsening phenomenon which builds upon the classical Ostwald ripening solution, with key inputs determined via thermofluid and thermochemical models. Predictions of oxide size are validated through comparison with experimental measurements on AM MA754, manufactured through LPBF and DED. Finally, two competing mechanisms (particle-pushing-induced agglomeration versus convection-aided runaway coarsening) are shown to explain experimental observations of large oxide slag inclusions.
4:05 PM
Oxide Coarsening Effects during Melt-based Additive Manufacturing: Experiment and Characterization: Timothy Stubbs1; Roger Hou2; Zachary Cordero2; Yuman Zhu1; Aijun Huang1; 1Monash University; 2Massachusetts Institute of Technology
Oxide dispersion-strengthened (ODS) superalloys utilize a uniform nano-scale oxide dispersion to stabilize and strengthen their microstructure in extremely demanding environments. Due to the limited manufacturing flexibility and high cost of producing these materials conventionally, there has recently been attention given to Additive Manufacturing (AM) techniques for producing near-net-shape products with minimal dispersoid coarsening and slagging. This study investigates the production of MA754 (Ni-20Cr-1Fe-0.3Al-0.5Ti-0.05C-0.6Y2O3 wt.%) via Directed Energy Deposition (DED) and Laser Powder Bed Fusion (L-PBF) from mechanically alloyed feedstock. The as-printed material is relatively defect free but contains significantly coarsened dispersoids and large oxide slag inclusions which weaken the material. The dispersoids and slag were shown through correlative EDS-EBSP analysis to contain Y-Al-O compounds, indicating that initially-pure Y2O3 reacts with the alloying aluminum during the brief melt cycle. Mitigating the effect of this reaction on dispersoid coarsening and agglomeration will therefore be the key to successful AM of ODS superalloys.
4:25 PM
A Calibration-Free Physics-based Framework to Predict Printability Maps in Additive Manufacturing Process: Sofia Sheikh1; Pejman Honarmandi1; Brent Vela1; Peter Morcos1; Raymundo Arroyave1; Ibrahim Karaman1; Alaa Elwany1; 1Texas A&M University
In additive manufacturing (AM), to fabricate porosity-free parts, the optimal processing conditions need to be determined. To do so, the design space for an arbitrary alloy must be analyzed to identify areas of defects for different power-velocity combinations, which can be visualized using a printability map, which can be costly. We have created a fully computational framework to reduce the cost and effort of constructing printability maps. The framework predicts material properties using CALPHAD models and a reduced-order model. Then, the analytical Eagar-Tsai thermal model uses the material properties to calculate the melt pool geometry during the AM processing. Finally, the printability maps are constructed using material properties, melt pool dimensions, and criteria for lack of fusion, keyholing, and balling defects. Using NiTi-based alloys, the framework is validated with experimental observations to compare and benchmark the defect criteria and find the optimal criterion set with the maximum accuracy.
4:45 PM
Development of a Methodology for AM-compatible Rapid Alloy Development: Philipp Stich1; Markus Apel2; Mustafa Megahed3; Patrick Köhnen4; Christian Haase5; 1EOS GmbH; 2Access e.V.; 3ESI Group; 4DAP, RWTH Aachen; 5IEHK,RWTH Aachen
In accordance with recent efforts to design new alloys available for AM processing, this study is contributing towards the development of a methodology for alloy development through a combination of theoretical and physical alloy screening. A hard-to-weld nickel-based superalloy is initially produced and parameterized on an EOS-M290. The LPBF-process is simulated to calculate the thermal conditions occurring under varying energy inputs. Elements critical to hot cracking, which were identified using various microstructural characterization techniques, are varied simulatively (phasefield + CALPHAD) to characterize their segregation behaviour within the calculated thermal boundary conditions.Being able to understand the undergoing mechanism leading to crack occurrence, we now derive criteria for an automated CALPHAD-based alloy screening tool, that can rapidly calculate from large alloy design spaces. Modifications of the reference alloy are atomized and processed. By comparison to the reference alloy, the next iteration for the alloy development is initialized.