Texture of TiNi shape memory alloy sheets produced by roll-bonding and solid phase reaction from elementary metals

We have developed a new process to produce Ti-Ni shape memory alloys from titanium and nickel sheets. This process is composed of repetitive roll-bonding for producing a Ti/Ni laminated sheet from them, and of subsequent heat treatment for forming a TiNi intermetallic phase by reactive diffusion. The Ti/Ni laminated sheet changed to a nearly single phase TiNi material through the formation of Ti2Ni and Ni3Ti intermediate products. TiNi sheets obtained by this process consisted of a near <111>//ND texture such as {223}<110> in the B2 austenite phase. Recoverable strain associated with martensitic transformation of TiNi was fairly isotropic in the sheet plane due to the relatively isotropic character of {111} texture. The formation of such texture through phase transformations by reactive diffusion has been discussed in view of texture inheritance