Electronic Structure Approach to Hydrogen Embrittlement in fcc Transition Metals

Summary

The electronic origin of hydrogen embrittlement in fcc transition metals is studied by, comparing electronic structure variations with lattice displacement in Pd and Ag. The electronic structure variations with cleaving and slip on the (111) plane have been calculated using the tight binding method that reproduces ab initio band structure calculations. The computed results show that lattice displacement increases the electron energy of Pd relative to that of Ag. In other w ords, electrons in Pd have a higher resistance to lattice displacement than those in Ag. This is caused by a difference in contributions of d and s-p electrons to the energy variation between Pd and Ag. Based on the computed results, the electronic origin of hydrogen embrittlement in Pd is discussed.