Elucidating hydrogen assisting vacancy formation in metals: Mo and Nb as examples
1 Department of Physics, Yantai
2 Department of Materials Science and Engineering, The Pennsylvania State University, University Park, 16802 Pennsylvania, USA
Received in final form: 8 July 2013
Published online: 7 August 2013
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 Hn-vacancy (HnV) complexes. The concentrations of vacancies in the form of HnV 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.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2013