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6438 |
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Microstructural evolution and mechanical properties enhancement of cold-spray-additive-manufactured metals by friction stir processing:
case study of copper |
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Wenya Li* / Northwestern Polytechnical University, P.R. China Kaiwei Hu / School of Materials Science and Engineering, Northwestern Polytechnical University, PR China Congcong Cao/ School of Materials Science and Engineering, Northwestern Polytechnical University, PR China Yaxin Xu/ School of Materials Science and Engineering, Northwestern Polytechnical University, PR China Xiawei Yang/ School of Materials Science and Engineering, Northwestern Polytechnical University, PR China |
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Cold spraying (CS) has been widely applied to deposit most metals and alloys, and metal matrix composites due to its unique solid-state nature, and has now been recognized as the cold spray additive manufacturing (CSAM) process. However, the relatively poor strength and extremely bad plasticity limit its applications as fabricating structural components. Besides the common post-spray annealing treatment, another effective method, i.e. friction stir processing (FSP), was tried recently. In this study, pure copper deposits were fabricated by CSAM and then FSPed. The results show that there are ultrafine equiaxed grains in the stir zone (SZ) after FSP, which are much different from the flattened particles and elongated grains for CSed Cu deposits, totally changing the topological relation of particles. The mechanical properties have a great improvement after FSP with the ultimate tensile strength from 82 MPa to 310 MPa, and more interestingly the elongation from about 0.8% to about 17.8%. The fracture mode of the Cu deposits changes from quasi-brittle to completely ductile. |