Patent ID: 7371295
Filing Date: 2008-05-13
Classification: C22C,C22F

Abstract:
1. A shape memory alloy comprising Co, Ni and Al, wherein said shape memory alloy has a two-phase structure comprising a β-phase having a B2 structure and a γ-phase having an fcc structure, at least 40% by area of crystal grain boundaries of said β-phase being occupied by said γ-phase and the fraction of said γ-phase volume in said shape memory alloy being 5 to 50% by volume, wherein said alloy contains 23 to 27 atomic % of Al and 39 to 45 atomic % of Co, the balance being 28 to 38 atomic % of Ni and inevitable impurities, and wherein said alloy has a tensile strength of about 400-1100 MPa and a shape recovery of 18% or more.