Eur. Phys. J. B (2013) 86: 355
https://doi.org/10.1140/epjb/e2013-40552-x

Regular Article

Elucidating hydrogen assisting vacancy formation in metals: Mo and Nb as examples

¹ Department of Physics, Yantai University, Yantai 264005, P.R. China
² Department of Materials Science and Engineering, The Pennsylvania State University, University Park, 16802 Pennsylvania, USA

^a e-mail: liuyuelin@ss.buaa.edu.cn

Received: 10 January 2013
Received in final form: 8 July 2013
Published online: 7 August 2013

Abstract

Impurity H is inclined to be trapped by some defects with more space such as vacancy and grain boundary when it dissolves in a metal. Inversely, H can also enhance formation of large amount of vacancies even if there are few vacancies in intrinsic metals initially. Using first-principles simulation combined with statistical model, Mo and Nb as examples, we quantitatively calculate the concentration of vacancies including pure vacancy and H_n-vacancy (H_nV) complexes. The concentrations of vacancies in the form of H_nV notably increase due to the decrease of effective formation energy of vacancy from H stimulation. Our finding solves a long-standing puzzle on the atomistic mechanism underlying H assisting vacancy formation in some metals.