Influence of hydrogen environment on dislocation nucleation and fractureresponse of〈110〉grain boundaries in nickel

Authors

Jiaqing Li, University of WollongongFollow
Cheng Lu, University of WollongongFollow
Linqing Pei, Chongqing UniversityFollow
Che Zhang, University of WollongongFollow
Rui Wang, University of WollongongFollow
Anh Kiet Tieu, University of WollongongFollow

RIS ID

135142

Publication Details

Li, J., Lu, C., Pei, L., Zhang, C., Wang, R. & Tieu, K. (2019). Influence of hydrogen environment on dislocation nucleation and fractureresponse of〈110〉grain boundaries in nickel. Computational Materials Science, 165 40-50.

Abstract

The segregation of solute H has a profound effect on mechanical properties of grain boundaries (GBs). In this work, systematic molecular dynamics (MD) simulations have been performed to elucidate the influence of H environment on dislocation nucleation process and fracture response of different Ni GBs. The results show that the effect of H on dislocation nucleation depends strongly on GB structures. The presence of H decreases the yield stress required to nucleate dislocations from GBs with C and D structural units (SUs), while increases the yield stress of GBs with E SUs. This difference is attributed to different deformation mechanisms related to the dislocation nucleation from various GBs with H. By analysing the decohesion results, it is found that H has stronger embrittling effect on GBs with E SUs than C and D SUs, originating from the fact that H significantly elongates the Ni-Ni bonds around the open E SUs while slightly expands the compact C and D SUs. These findings present fundamental understanding on H embrittlement mechanism and provide mechanistic insights for engineering microstructure against H embrittlement in metallic materials.

Grant Number

ARC/DP170103092