Age-hardening mechanisms of heterogeneous-nanostructured SUS316LN stainless steel fabricated by heavy cold rolling

冷間強圧延で製造したヘテロ構造化SUS316LNステンレス鋼の時効硬化機構

三浦 博己*; 渡邊 千尋*; 青柳 吉輝*; 大場 洋次郎  ; 小林 正和*; 吉永 直樹*

Miura, Hiromi*; Watanabe, Chihiro*; Aoyagi, Yoshiteru*; Oba, Yojiro; Kobayashi, Masakazu*; Yoshinaga, Naoki*

The nanostructure produced by heavy cold rolling provides tensile strength of 1.9 GPa in SUS316LN austenitic stainless steel, which is further raised up to 2.2 GPa by peak aging at 748 K. Nanostructural observations using electron microscopes, small-angle scattering, and atom probe tomography revealed segregation of solute elements of Mo, Si, and so on at twin and low-angle lamellar boundaries. Finite element calculation demonstrates that this grain-boundary segregation can increase the mechanical strength.