Atomistic simulations of phase transformation of copper precipitation and its effect on obstacle strength in -iron

Tsuru, Tomohito   ; Abe, Yosuke; Kaji, Yoshiyuki  ; Tsukada, Takashi ; Jitsukawa, Shiro

The size- and spacing- dependent obstacle strength due to the Cu precipitation in -Fe is investigated by atomistic simulations, in which the effect on phase transformation of Cu precipitation is considered by a conventional self-guided molecular dynamics (SGMD) method that has an advantage to enhance the conformational sampling efficiency in MD simulations. It was shown that the SGMD method can accelerate calculating the bcc to 9R structure transformation of a small precipitate, enabling the transformation without introducing any excess vacancies. Such metallographic structures increase the obstacle strength through strong pinning effects as a result of the complicated atomic rearrangement within the Cu precipitation.