Phase Transformation and Deformation Behavior of Ti - Ni - al Shape Memory Alloys .
이오연O . Y . Lee, 이순난H . N . Lee, 천병선B . S . Chun
Abstract
The effect of heat treatments and cold reduction on the martensitic transformation and pseudoelasticity behavior in Ti-Ni-Al alloys has been investigated by means of electrical resistance measurement, tensile test, optical and transmission electron micros copy. The transformation temperatures have linearly decreased with the increase of Al content and R-phases have been formed along the grain boundary. The thermal hysteresis of R-phase transition has been hardly affected by cold reduction, but that of martensitic transformation has been remarkably increased. The critical stress for the first stags in Ti_(50)Ni_(49)Al_(1.0) alloy is almost costant (40∼50 Mpa) irrespective of cold reduction, but that of stress induced martensite is considerably increased.