[1] Ibaraki Univ, Dept Mat Sci & Engn, Hitachi, Ibaraki 3168511, Japan
[2] Russian Acad Sci, Inst Met Superplast Problems, Ufa 450001, Russia
[3] Tohoku Univ, Grad Sch Engn, Dept Mat Proc, Sendai, Miyagi 9808579, Japan
[4] Ibaraki Univ, Grad Sch Sci & Engn, Ibaraki 3168511, Japan