Charpy absorbed energy of ultrafine-grained Ti-6Al-4V alloy at cryogenic and elevated temperatures

Abstract

The dependence of the absorbed energy of ultrafine-grained (UFG) Ti-6Al-4V alloy on the test temperature is studied. Tensile tests and Charpy tests were carried out at room temperature, cryogenic temperature, and temperatures elevated up to 500 °С. A UFG state was produced by equal-channel angular pressing. For the sake of comparison, coarse-grained (CG) alloy was subjected to heat treatment to produce a duplex structure. The UFG alloy demonstrates enhanced strength and reduced ductility-related properties at room temperature. It is shown that at operating temperatures of 200 and 300 °С, the best balance between high strength and absorbed energy is achieved in the UFG alloy. The UFG alloy demonstrates higher strength compared to the CG alloy at the liquid nitrogen temperature, but their absorbed energy is practically the same. The failure mechanisms of CG and UFG alloy and promising engineering applications of UFG alloy are discussed.