Introduction of Mille-Feuille-Like α/β Layered Structure into Ti–Mo Alloy

As a trial to realize kink band strengthening in titanium alloys, slight cold rolling followed by aging heat treatment were applied on Ti–12 mass% Mo alloys for obtaining mille-feuille-like layered hcp (α)/bcc (β) two phase structure. After slight cold rolling at rolling reduction of 5% and subsequent aging heat treatment at 973 K for 180 ks, plate-like α phases were precipitated in the β phase matrix and made an alternately stacked mille-feuille-like α/β layered structure. These α phases were precipitated on the boundary of {3 3 2}〈1 1 3〉 β type deformed twins introduced in the β phase matrix during the slight cold rolling. The thin film-like α phase precipitated at a very early stage of aging, and became thicker during aging to produce the mille-feuille-like α/β layered structure.