Work

Effects of helium and vacancy in Ni symmetric tilt grain boundaries by first-principles

Year: 2024

Type: article

Abstract: The vacancy and helium effects on eight low-Σ symmetric tilt grain boundaries (STGBs) of Ni were investigated by first-principles calculations. The simulations demonstrate that vacancies in Ni matrix could diffuse easily to the grain boundary and helium atoms are quite stable at the grain boundary vacancy sites. Vacancy accumulation at high-energy STGBs could enhance the binding strength while He defects are generally detrimental to grain boundary binding and interstitial helium defects can initiate more severe grain boundary cracking comparing to vacancy-bind-helium. Further electron charge analysis suggested the influence of grain boundary binding greatly relies on the grain boundary atomic structure and the interaction between Ni-d and He-p states. The polarized charge transfer induced by He helium occupation was predicted to be detrimental to the binding strength, which explains the experimentally-observed helium bubbles and helium-induced GB embrittlement .

Source: Nuclear Materials and Energy

DOI: 10.1016/j.nme.2024.101721

Authors: Yiren Wang, Jintong Meng, Fan Jia, Fuhua Cao, Yong Jiang

Institution: Central South University

Language: English

Topic: Fusion materials and technologies

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,840

Funders: National Natural Science Foundation of China, Central South University, Huxiang Youth Talent Support Program, Science and Technology Program of Hunan Province