Patent ID: 7988722

Claim:
A method for the thermal mechanical treatment of a nickel-titanium ternary alloy performed at temperatures <M d wherein the hysteresis is widened such that after the treatment is completed A s <A s ′, comprising the steps: a) annealing or partially annealing a NiTi ternary alloy through a high temperature solution treatment followed by cooling; b) mechanically straining the alloy be under a load while simultaneously cooling the material to a temperature around or less than M s , thus shifting A s up much higher such that A s <A s ′ and retaining a sufficient amount of strain in the strained element whereby if controlled deformation is applied the alloy is transformed to the austenitic phase, shifting A s ′ to A s ; and c) Applying controlled deformation whereby the alloy is transformed to the austenitic phase, wherein A s ′ is shifted to A s .