The effect of applied stress on the shape memory behavior of TiNi-based alloys with different consequences of martensitic transformations

摘要

The development of plastic deformation and shape memory behavior of the Ti49.5Ni50.5, Ti50Ni34Pt16, Ti50Ni39,25Cu10Fe0,75 alloys are studied. The alloys differ by consequences of martensitic transformations (MT). It is found that the behavior of both accumulated and returned strain components exhibit some features in the alloys under consideration. The strain-temperature diagrams of the Ti49.5Ni50.5 alloy with the B2<---->B19' MT are of the one-step form. There are three stages on the strain-stress curves of this alloy depending on value of the applied mechanical torque. The regularity of plastic behavior of the Ti50Ni34Pt16 alloy with the B2<---->B19 transformation is similar to that of the Ti49.5Ni50.5 alloy. The strain-stress diagram has three stages. However, there is a significant difference in the shape memory behavior of this alloy. The shape-memory behavior of the Ti50Ni39,25Cu10Fe0,75 alloy corresponds to the two-stage nature of its B2<----> B19<---->B19' MT. The deformation mechanisms for these stages have their features in contrast to those of the foregoing alloys. The strain and temperature parameters of the shape memory effect and plastic behavior of the TiNi-based alloys are also examined. (C) 2003 Elsevier B.V. All rights reserved. [References: 7]