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Free keywords:
Annealing; Cellular automata; Chromium alloys; Cobalt alloys; Entropy; Hydrogen; Hydrogen embrittlement; Iron alloys; Manganese alloys; Melting; Plasticity; Selective laser melting; Strain rate; Tensile testing, Cellular structure; Crack initiation and propagation; Dislocations densities; Electrochemical hydrogen charging; Embrittlement resistance; High entropy alloys; Local plasticity; Selective laser melting; Slow strain rate tensile test; Twin cell, High-entropy alloys
Abstract:
We demonstrate that modifying the cellular structures by well-controlled annealing can effectively improve the hydrogen embrittlement (HE) resistance of selective laser melting (SLM) processed alloys. Investigations on both as-SLM processed and annealed prototype CoCrFeMnNi high-entropy alloy samples suggest that annealing preserved the cellular structures while effectively reduced the dislocation densities. This slightly reduced the strength but significantly increased the ductility and HE resistance upon slow strain rate tensile tests (1 × 10−5 s-1) under in situ electrochemical hydrogen charging. The crack initiation and propagation were delayed by hydrogen-enhanced local plasticity with the formation of nano-twins and dislocation cells in the modified structures. © 2021 Elsevier Ltd
