Additive Manufacturing: Beyond the Beam III: Cold Spray
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Powder Materials Committee, TMS: Additive Manufacturing Committee
Program Organizers: Brady Butler, US Army Research Laboratory; Peeyush Nandwana, Oak Ridge National Laboratory; James Paramore, Texas A&M University; Nihan Tuncer, Desktop Metal; Markus Chmielus, University of Pittsburgh; Paul Prichard, Kennametal Inc.
Tuesday 8:00 AM
March 1, 2022
Room: 263B
Location: Anaheim Convention Center
Session Chair: Zach Levin, Los Alamos National Laboratory; Brady Butler, DEVCOM ARL
8:00 AM Introductory Comments
8:10 AM
Effect of Laser Heating on Microstructure and Deposition Properties of Cold Sprayed SS304L: Christopher Roper1; Anita Heczel1; Venkata Satish Bhattiprolu2; Jeno Gubicza3; Tamas Kolonits3; Luke Brewer1; 1The University of Alabama; 2South Dakota School of Mines and Technology; 3Eötvös Loránd University
The effects of laser heating on the microstructure and mechanical properties of cold sprayed 304L stainless steel (SS304L) was investigated. Three SS304L cold sprayed samples were made, then two samples were laser heated post cold spray to 750℃ and 950℃. The resulting microstructure and mechanical properties were studied. Electron backscatter diffraction (EBSD) and X-ray line profile analysis (XLPA) were used to determine the microstructure and dislocation density in the three depositions both near the surface of the deposition and near the interface of the deposition with the substrate. It was found that laser heating caused recrystallization in the material and ultimately grain growth, which correlated with a significant decrease in dislocation density in the material and a reduction in hardness for the laser heated deposits. This points to the ability of laser surface heating for effective microstructural manipulation of cold sprayed materials.
8:30 AM
Mesoscale Simulation of Cold Spray Microstructure Formation: Theron Rodgers1; Jacob Mahaffey1; 1Sandia National Laboratories
Cold spray deposition is a promising method of fabricating coatings and performing structural repairs with minimal heating of the deposited material or substrate. Cold spray coatings feature a complex microstructure that differs from both bulk materials and coatings generated by melting-based thermal spray processes (plasma spray, HVOF, etc). Significant progress in understanding single-particle impact dynamics has been made using hydrodynamic and molecular dynamics simulations, but there are no methods capable of simulating coating formation from repeated (> 1,000) particle impacts. Here we introduce a 3D rules-based simulation method for the generation of full-thickness synthetic coating microstructures. The method is based on a model developed for plasma spray processes but incorporates substrate deformation and erosion. In this presentation, the method will be introduced, its ability to simulate different deposition regimes discussed, and a comparison with experimental microstructures performed. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
8:50 AM
Influence of Hydrogen Content and Particle Size Distribution on the Microstructure of Tantalum Cold Spray Coatings: Kliah Soto Leytan1; Mahsa Amiri1; Lorenzo Valdevit1; Daniel Mumm1; 1University of California, Irvine
The effects of two distinct tantalum feedstock powder properties on the microstructure of the resulting cold spray coating were investigated through high resolution characterization. Hydrogen content and particle size distribution (PSD) of feedstock powders both play a role in the extent of deformation and bonding between particles that takes place during the cold spray process. Hydrogen is introduced as impurities during processing of powders and/or long-term storage and it has been shown to negatively impact the mechanical properties of bulk tantalum, while the overall shape of the PSD (specifically the end tail) is thought to affect the quality of bonding between particles (especially larger, slower ones). In this work, we systematically and independently varied both the hydrogen content and the PSD of the feedstock powders and investigated the resulting cold spray coatings through SEM and HRTEM to identify potential differences in extent of deformation, bonding, and porosity, among others.
9:10 AM
Practical Considerations for Complex Path Planning for Cold Spray Additive Manufacturing.: Christopher Massar1; 1Worcester Polytechnic Institute
With advancements in the cold spray community, simple geometric consolidations for flat plate and similar builds are becoming more commonplace. These depositions are appropriate for the demonstration of the capability of being able to deposit material, or a combination of materials but the spray approach does not necessarily translate well to complex geometry. A practical approach to deposition of, for example, a wear-resistant coating on a complex geometry will be discussed herein. The objective of this presentation is to address key practical path planning logistics in conjunction with surface preparation techniques to help optimally deposit various powders ranging from softer alloys like copper and aluminum to hard steels and wear-resistant coatings. Moreover, considerations like masking can play a critical role in the successful deposition will be discussed.