Additive Manufacturing of Refractory Metallic Materials: Additive Manufacturing of W-based Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee
Program Organizers: Antonio Ramirez, Ohio State University; Jeffrey Sowards, NASA Marshall Space Flight Center; Omar Mireles, NASA; Eric Lass, University of Tennessee-Knoxville; Faramarz Zarandi, RTX Corporation; Matthew Osborne, Global Advanced Metals; Joao Oliveira, Faculdade Ciencias Tecnologias
Wednesday 8:30 AM
March 22, 2023
Room: 24A
Location: SDCC
Session Chair: Antonio Ramirez, The Ohio State University; Omar Mireles , NASA MFSC - EM32
8:30 AM
Rhenium Modified Spherical Tungsten Powder for Additive Manufacturing: Adriana Wrona1; Marcin Lis1; Krzysztof Pęcak1; Anna Janoszka1; Adam Sekuła1; Monika Czerny1; Jacek Mazur1; Adrian Kukofka1; 1Lukasiewicz Research Network — Institute of Non-Ferrous Metals
Tungsten has recently piqued interested as the potential precursor for L-PBF techniques. However due to its inherent thermal characteristics it has been thus far impossible to produce pure tungsten prints without networks of cracks and porosities forming on and underneath the surface. Many solutions have been proposed to mitigate this issue, both technological and material. In this work we are proposing novel material solution which consists of manufacturing of modified tungsten powder with spherical particle morphology. Based on well established ‘’rhenium ductile effect”, we propose Re modified W powder as the precursor for the additive manufacturing technologies. This work describes synthesis method of modified W-Re powders by means of thermal reduction and plasma spheroidization. For received powders further characteristics have been tested: physical properties, microstructure, grain homogeneity as well as chemical and phase composition.
8:50 AM
Crack Mitigation Strategies for Pure Tungsten via Laser Powder-bed-fusion: Alberico Talignani1; Shiqi Zheng1; Philip DePond2; Maria Strantza2; Jianchao Ye2; Y. Morris Wang1; 1University of California, Los Angeles; 2Lawrence Livermore National Laboratory
Laser powder-bed-fusion (L-PBF) of pure tungsten combines the remarkable properties of the element, which make it suitable for applications in extreme environments, with a freedom of design that is largely unmatched in metal additive manufacturing. Tungsten is susceptible to cracks during manufacturing because of its high ductile-to-brittle transition temperature (DBTT). To date, the issue of cracking in tungsten manufactured via L-PBF has not been resolved. We report our progress on the processing control of L-PBF tungsten and its role in crack mitigation. A variety of laser parameters, as well as different types of L-PBF machines, have been used to uncover strategies to suppress cracks. Processing models are under development to help enhance our understanding of cracking behavior in pure tungsten.The work at Lawrence-Livermore-National-Laboratory was performed under auspices of Department of Energy under contract DE-AC52-07NA27344.
9:10 AM
Development of W-based Alloys for High Temperature Applications by Additive Manufacturing: Ishtiaq Ahmed F Rabbi1; Narendra Dahotre1; 1University of North Texas
Through the elimination of manufacturing issues including high-temperature thermomechanical processing and machining, additive manufacturing (AM) presents numerous potentials to expand the application of refractory metals and alloys. W, which has excellent high temperature mechanical properties and a high elastic modulus, can serve as a good base material for the creation of novel AM alloys for improved high temperature performance. The obstacles to successfully printing of W-based alloy, however, are high heat conductivity and high ductile to brittle transition temperature. The objective of this study is to evaluate whether W-xCr wt.% alloys can be manufactured using additive laser manufacturing. Process parameters and powder prototypes were optimized for printing an alloy with a greater relative density. Microstructure and mechanical properties of AM-fabricated specimens were studied by analyzing the phases evolution, grain orientation and size, as well as comparing the mechanical performance of various compositions.
9:30 AM
ICME Analysis Microcracking of Tungsten in Rapid Solidification: Tatu Pinomaa1; Jukka Aho1; Matias Haapalehto1; Joni Kaipainen1; Sicong Ren1; Paul Jreidini2; Joseph McKeown3; Jesper Byggmästar4; Kai Nordlund4; Nikolas Provatas2; Anssi Laukkanen1; 1VTT Technical Research Centre of Finland Ltd; 2McGill University; 3Lawrence Livermore National Laboratory; 4University of Helsinki
Tungsten is used as a plasma facing material for fusion reactors due to its high melting point, thermal conductivity, and low fuel retention. While additive manufacturing is a promising method to produce tungsten parts, it tends to produce microcracks. We perform a multiscale modeling analysis to explore the rapid solidification features of pure tungsten and certain tungsten-based binary alloys. We use a gaussian approximation potential MD and phase field crystal to analyze rapid solidification defects, including point defects, dislocations, crystal orientation gradients, and potential microcavities. On continuum scale, we perform coupled phase field and crystal plasticity simulations to investigate microstructural (type II-III) residual stresses due to solidification shrinkage, and due to solid-state thermal contraction during cool-down. The simulation results are compared to bare plate single line scans. We discuss the role of ductile-to-brittle transition and oxide inclusions as sources of microcracking, and the effect of selected alloying elements on microcracking.
9:50 AM Break
10:10 AM
Materials and Processing Design for Binder Jet Additive Manufacturing of Tungsten Alloys: Daozheng Li1; Wei Xiong1; 1University of Pittsburgh
Tungsten alloys have many potential ultra-high-temperature applications. However, due to the high melting and the ductile-to-brittle-transition temperature, tungsten alloys usually have low manufacturability, limiting their applications. This work proposes a new concept to advance BJAM (Binder Jet Additive Manufacturing) technology for tungsten alloy (pure tungsten with alloy binder) with high mechanical performance. To facilitate the sintering process, a new refractory alloy binder is designed for printing and sintering using the CALPHAD-based ICME (CALPHAD: Calculation of Phase Diagrams, ICME: Integrated Computational Materials Engineering) modeling. With the achievements of higher density, yield, and ultimate tensile strength and ductility than existing tungsten alloys made by additive manufacturing, this work approves the possibility of utilizing the BJAM technique to reach the target properties and complicated designs.
10:30 AM
Processing, Structure, and Properties of Electron Beam Melting Additively Manufactured Pure Tungsten: Christopher Ledford1; Patxi Fernandez-Zelaia1; Tim Graening1; Yutai Kato1; Michael Kirka1; 1Oak Ridge National Laboratory
The layer-wise additive manufacturing approach enables opportunities for producing complex geometries from refractory metals which cannot be otherwise achieved via powder metallurgy. However, the processing science is still in its nascent stage and structure-property relations are relatively unexplored. Here we focus on the processing of pure tungsten using electron beam melting AM. Experimentally we develop a suitable processing window for achieving high density crack free material. Microstructural analysis reveals that the microstructure generally consists of a columnar structure with a (111) build direction fiber preference, although, fiber switching was also observed. At a smaller length scales subgrains were observed which are believed to form due to process induced deformation. High temperature tensile testing reveals that the material exhibits excellent strength and ductility. Significant mechanical anisotropy was observed which is likely driven by crystallographic texture.
10:50 AM
Investigating AM High Temperature Multi-materials with Nickel and Niobium Alloys: Soumya Nag1; Brian Jordan1; Ke An1; Chuan Zhang2; Fan Zhang2; Raymond Unocic1; Jonathan Poplawsky1; Jaimie Tiley1; 1Oak Ridge National Laboratory; 2Computherm LLC
Additive manufacturing (AM) provides a tremendous opportunity to synergistically couple materials, design, and manufacturing strategies. To make AM a substantial manufacturing strategy, one must incorporate its unique attributes of optimizing alloy composition, design and manufacturing modalities to fit site-specific performance needs, by tailoring metal-metal or metal-ceramic compositional transitions. The current effort explores alloys that are being used at high temperatures and extreme environments – specifically to investigate phase transformations and deformation mechanisms in additively manufactured Ni-base superalloys (IN718) graded to Nb-based refractory alloys (C103). The study will enable synergistic coupling of experimental and modeling tools to design pathways for compositional gradation and understand the thermal response on phase/stress evolution of additive builds in a spatio-temporal manner. This concept is really material agnostic, and can be beneficial for fabricating parts with targeted site-specific properties for a wide range of applications in extreme environments in aviation, space, and energy sectors.