Powder Metallurgical Components in High Performance Applications: Session I
Sponsored by: TMS Powder Materials Committee
Program Organizers: Peng Cao, The University of Auckland; Hanadi Salem, American University in Cairo; Paul Prichard, Kennametal Inc.; Matthew Osborne, Global Advanced Metals; James Paramore, Texas A&M University
Tuesday 2:00 PM
October 19, 2021
Room: A213
Location: Greater Columbus Convention Center
Session Chair: Hanadi Salem, American University in Cairo
2:00 PM
Development of Resistance Based Sintering for Metal Powders: Jerry Gould1; James Cruz1; 1Edison Welding Inst
Resistance based sintering employs axial pressure and in-situ heating to accomplish consolidation. Conventional methods of resistance based sintering (SPS\FAST) have been based paralleling hot isostatic processing (HIPing), using diffusion to accomplish consolidation. The result has resulted in significantly higher productivity compared to HIPing, but still requires processing times on the order of an hour and active gas shielding. In this work, the process has been re-imagined as a complex series of projection welds between contacting particles. The re-imagined technology results in the use of higher currents, dramatically shorter cycle times, and is done without shielding. Initial work has been done with titanium powders. Processing has been developed resulting in full densification in roughly 3 seconds, with contact stresses on the order of 35-MPa. During processing, peak temperatures less than 1000-deg C were experienced. This resulted in a fully β-transformed microstructure with a subsequent Widmenstätten α+β morphology.
2:20 PM
Dispersing Tailored Nanoparticles through Powder Metallurgy Consolidation: Bahrum Rocky1; Rofiques Salehin2; Christopher Weinberger2; Steve Daniewicz1; Gregory Thompson1; 1University of Alabama; 2Colorado State University
While solid-state precipitation routes can readily yield a dispersion of nano-precipitates, the tailoring of such phases can be difficult owing to thermodynamic and kinetic precipitation conditions. In contrast, powder metallurgy (PM) consolidation can readily incorporate tailored nano-precipitates via specifically synthesized nanoparticles that are placed into the matrix. However, the uniform dispersion of such nanoparticles with micron-sized powders can be difficult. In this presentation, the fabrication routes for dispersing transition metal carbide (TMC) nanoparticles into ferrous matrix powders are discussed using various surfactants and/or high energy ball milling methods to identify the optimal mechanochemical techniques that provide a uniform TMC dispersion. The aim of which is to capture specifically tailored TMCs that are computationally predicted to trap hydrogen improving the strength and resistance to hydrogen embrittlement. The dispersion and PM processing routes are discussed in terms of consolidation, mechanical strength, and hydrogen charging/trapping potentials.