The hydrogen embrittlement of pure Ni fabricated by additive manufacturing

This work investigated the hydrogen embrittlement mechanism of Ni fabricated by laserbased powder bed fusion (L-PBF). In the presence of hydrogen, the L-PBFed Ni failed with a brittle mode, while its fracture surface had a transgranular-like appearance. This unusual fracture morphology is rooted in the special grain shape induced by the laser-based manufacturing process, and the failure process is actually predominated by the intergranular decohesion. An annealing process of the as-printed sample enhanced its elongation and mitigated the hydrogen embrittlement. The special dislocation cellular pattern formed in additive manufacturing is considered to be detrimental to hydrogen embrittlement resistance.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the mechanism of hydrogen embrittlement in Ni fabricated by laser-based powder bed fusion. In the presence of hydrogen, the Ni failed in a brittle mode with a transgranular-like fracture surface. This unusual fracture morphology is caused by the special grain shape induced by the laser-based manufacturing process, and the failure process is mainly attributed to intergranular decohesion. Annealing of the printed sample improved its elongation and mitigated hydrogen embrittlement. The dislocation cellular pattern formed in additive manufacturing is considered detrimental to hydrogen embrittlement resistance.