Effect of Yttrium on Microstructural Evolution and High Temperature Compressive Behavior of Ti-Ni-Hf High Temperature Shape Memory Alloys

摘要

The effect of yttrium (up to 4.5 at.%) on the microstructural evolution and hot compressive behavior of Ti-Ni-Hf high temperature shape memory alloys was investigated. For these purposes, hot compression tests and X-ray diffraction pattern analyses were carried out. The addition of yttrium significantly reduced the compressive ductility of the Ti-Ni-Hf alloy because of the formation of brittle yttrium-rich phases. The effect of the brittle phase was simulated by the finite element approach with the cohesive zone model.