Additive Manufacturing: Materials Design and Alloy Development III -- Super Materials and Extreme Environments: Microstructural Aspects
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee
Program Organizers: Behrang Poorganji, Morf3d; Hunter Martin, HRL Laboratories LLC; James Saal, Citrine Informatics; Orlando Rios, University of Tennessee; Atieh Moridi, Cornell University; Jiadong Gong, Questek Innovations LLC
Tuesday 8:30 AM
March 16, 2021
Room: RM 3
Location: TMS2021 Virtual
Session Chair: Orlando Rios, University of Tennessee
8:30 AM Invited
Microstructure Evolution of Metallic Alloys under Additive Manufacturing Conditions: Amy Clarke1; Jonah Klemm-Toole1; Behnam Aminahmadi1; Chloe Johnson1; Alec Saville1; Brian Rodgers1; Jeremy Shin1; Kamel Fezzaa2; Sven Vogel3; Joseph McKeown4; Tresa Pollock5; Alain Karma6; 1Colorado School of Mines; 2Advanced Photon Source, Argonne National Laboratory; 3Los Alamos National Laboratory; 4Lawrence Livermore National Laboratory; 5University of California Santa Barbara; 6Northeastern University
Solidification is the first step encountered during additive manufacturing (AM). Combinations of thermal gradient and solid/liquid interface velocity are known to significantly impact microstructure (and defect) evolution, including potential grain refinement produced by the columnar to equiaxed transition. A deeper understanding of solidification and solid state phase transformations under AM conditions is needed to guide the design of alloys for AM. We must ultimately match microstructure evolution to the conditions experienced during AM, including repeated cycles of heating and cooling. In-situ visualization by experimentation and modeling of phase transformations and microstructure evolution is needed to achieve this aim. Here we highlight new insights into microstructure evolution under AM conditions obtained by multiscale, in-situ/ex-situ characterization of metallic alloys, including conventional alloys, model alloys, and alloys designed for AM. These results will inform AM alloy development and enable the prediction and control of microstructure and property evolution under AM conditions.
9:00 AM Invited
Solidification Condition and Its Effects on Microstructure in Metal-power Bed Fusion Processes: Yuichiro Koizumi1; 1Osaka University
The solidification in Powder Bed Fusion (PBF) type additive manufacturing (AM) leads to material properties different from those obtained by conventional processes. We have examined the relationship between the solidification condition and grain structures in the PBF process by combining experiments and computer simulations. We found that equiaxed grains are formed even when columnar grains are expected according to the conventional columnar-equiaxed transition theory when the fluid velocity in melt-pools is as high as hundreds of mm/s. Phase-field simulations suggested that the solute segregation becomes more significant with increasing cooling rate. These findings are essential for developing new alloys suitable for AM. Reference: [1] Zhao et al. Additive Manufacturing 2019;26:202. [2] Sun et al. Acta Materialia 2015;86:305. [3] Wei et al. Additive Manufacturing 2018;24:103. [4] Ueki et al. Metals 2020;10:71. [5] Ding et al. Materials Science & Engineering A 2019;764:138058. [6] Sun et al. Additive Manufacturing 2018;23:457.
9:30 AM
Exploring the Structure-property Relationships of the Compositionally Graded WxCoCrFeMnNi High-entropy Alloy: Jonathan Pegues1; Michael Melia1; Benjamin Gould2; Raymond Puckett1; Shaun Whetten1; Nicolas Argibay1; Tomas Babuska1; Andrew Kustas1; 1Sandia National Laboratories; 2Argonne National Laboratory
Tungsten has been identified as a promising shielding material for high-temperature applications such as those involving plasma-material interactions. Utilizing an additive manufacturing-enabled high-throughput materials discovery framework, a tungsten graded high-entropy alloy was screened to establish first order structure-property relationships. Compact metallurgical WxCoCrFeMnNi specimens spanning x = 0 – 20 at. % were fabricated utilizing in-situ alloying enabled by powder based directed energy deposition. Microstructure evolution as a function of specific WxCoCrFeMnNi compositions was identified through a combination of XRD/XRF and SEM-EDS/EBSD. Microhardness measurements were also performed to rapidly establish baseline structure-property relationships. Functional composition maps identifying compositions that promote solid solutions, multiple phases, intermetallics, high hardness, and brittleness are discussed in relation to the alloy-specific microstructural characteristics and configurational entropy. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
9:50 AM
Structure-property Relationships of Additively Manufactured Ni-Nb Binary Alloys: Andrew Kustas1; Jonathan Pegues1; N. Scott Bobbitt1; Raymond Puckett1; Morgan Jones1; Michael Chandross1; Nicolas Argibay1; 1Sandia National Laboratories
Rapid solidification of laser-based metal additive manufacturing (AM) enables processing of unconventional alloys with unique metastable microstructures that are impractical to achieve conventionally. A number of emerging alloys have been explored with AM, such as refractory metals, high entropy alloys, and metallic glasses. This latter group of materials have been shown to develop amorphous structures when rapidly solidified via metal AM, reinvigorating the possibility of manufacturing near-net-shape bulk metallic glass parts. We implement a high-throughput alloy processing and characterization methodology to rapidly evaluate structure-property evolution across the Ni-Nb binary system, which exhibits a wide glass-forming compositional range. We also present the results of Molecular Dynamics simulations that provide insights into material properties across the range of compositions. This work serves as preliminary results of high-throughput experimental and computational tools that have been developed to accelerate AM materials development. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
10:10 AM
Microstructural and Mechanical Characterization of Additively Manufactured Al-Fe-V-Si: Paul Wilson1; Christopher Meyer1; Fatmata Barrie1; 1The Boeing Company
For high temperature applications, the Al-Fe-V-Si system has been of particular interest due to the formation of coarsening resistant and thermally stable α-Al(Fe,V)Si phase during rapid solidification. Several commercial alloys were developed, but are in limited use due to the difficulty and expense of processing. However, cooling rates in the laser powder bed fusion process approach those of traditional rapid solidification techniques, allowing for the possibility of revisiting rapid solidification systems. This study re-examines the Al-Fe-V-Si system for use in laser powder bed fusion. Initial parameter development was conducted and high density processing windows were found with no solidification cracking. Tensile and fatigue specimens were produced and tested for a preliminary evaluation. Additionally, the microstructure was investigated using transmission electron microscopy to compare to traditional rapidly solidified microstructures.
10:30 AM
Bulk Single Crystals in Cubic Systems Produced via Electron Beam Melting Additive Manufacturing: Patxi Fernandez-Zelai1; Michael Kirka1; Sebastien Dryepondt1; Yousub Lee1; Christopher Ledford1; 1Oak Ridge National Laboratory
Electron beam melting (EBM) additive manufacturing technologies are utilized for the processing of defect free high temperature metals. The precise control over the rapidly moving heat source enables site specific microstructure control. Recent works have shown the feasibility of printing bulk scale Ni-based superalloy single crystals via EBM. A grain selection mechanism, which is yet to be fully understood, generates crystals with a [001] build direction preference and [011] preference perpendicular to the line scan direction. In this work we investigate the mechanisms which drive this anomalous texture selection in several Ni-based superalloy systems using space-fill design of experiments, novel microstructure quantifiers, and physics based simulations. The inferred knowledge is utilized to generate novel microstructures not possible via traditional casting techniques. Feasibility for generating these structures in other high temperature cubic material systems is also demonstrated.
10:50 AM
A Comparison between In-situ and Ex-situ Mixing of Nanoparticles with a Matrix in Additive Manufacturing of Metal Matrix Composite: Somayeh Pasebani1; Milad Ghayoor1; Kijoon Lee1; Yujuan He1; Chih-hung Chang1; Brian Paul1; 1Oregon State University
Laser powder bed fusion (LPBF) process was utilized to embed nanoparticles of yttrium oxide (Y2O3) into the 304L stainless steel matrix. In first approach, mixture of 304L stainless steel powder and yttrium oxide particles was used as feedstock for fabricating parts using the LPBF process. In second approach, a novel hybrid method has been utilized to synthesize 304L ODS alloy using ink-jetting in the LPBF process. In this method, yttrium oxide nanoparticles selectively doped into the matrix by jetting precursor chemistry before laser conversion and consolidation. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed the precipitation of homogenously distributed Y-Si-O nanoparticles in the matrix of additively manufactured 304L ODS alloy in both approaches. The yield stress was 575±8 MPa and 586±9 MPa, respectively, in the first and second approaches, both showing higher mechanical properties compared to 304L and most conventionally manufactured 304L ODS alloys.