Effect of room-temperature aging on shape memory characteristics of Ti–10Nb–10Zr–11Ta (at.%) alloy

Abstract

In this study, the effect of room-temperature (RT) aging on the shape memory characteristics of the Ti–10Nb–10Zr–11Ta (at.%) alloy was investigated by tensile tests. Ingots were prepared using the arc melting method and then cold-rolled at a reduction of up to 95%. After cold-rolling, the plates were solution-treated at 1173K for 1.8ks, followed by aging at RT and temperatures up to ∼573K for various periods of times. Superior superelasticity was observed at RT in the solution-treated specimen. The critical stress for inducing martensitic transformation (σSIM), tensile strength, and critical stress for slip (σS) of specimens aged at RT increased with increasing aging time up to 60 days, showing no noticeable changes with further increases in the aging time. On the other hand, in the specimens aged at 373K, 423K, and 473K for 3.6ks, the values of σSIM and the tensile strength increased with increasing aging temperature, while the specimen aged at 573K exhibited mature fractures. There were little change in σSIM and σS of the specimen that was solution-treated followed by aging at 373K for 3.6ks during RT aging. This result indicated that aging at 373K resulted in good resistance against the effect of RT aging.