First-principles calculation of multiple hydrogen segregation along aluminum grain boundaries

Yamaguchi, Masatake   ; Ebihara, Kenichi   ; Itakura, Mitsuhiro  ; Tsuru, Tomohito   ; Matsuda, Kenji*; Toda, Hiroyuki*

The segregation of multiple hydrogen atoms along aluminum (Al) grain boundaries (GBs) and fracture surfaces (FSs) was investigated through first-principles calculations considering the characteristics of GBs. The results indicate that hydrogen segregation is difficult along low-energy GBs. The segregation energy of multiple hydrogen atoms along GBs and FSs and the cohesive energy was obtained for three types of high-energy Al GBs. With increasing hydrogen segregation along the GBs, the cohesive energy of the GB decreases and approaches zero with no decrease in GB segregation energy. The GB cohesive energy decreases in parallel with the volume expansion of the region of low electron density along the GB.