Effect of Stress Relieving Heat Treatment on the Microstructure and High-Temperature Compressive Deformation Behavior of Ti-6Al-4V Alloy Manufactured by Selective Laser Melting

초록

This study aims to investigate the effect of stress relieving heat treatment on the microstructure and high-temperature compressive deformation behavior of the Ti-6Al-4V alloy, manufactured by selective laser melting. Initial microstructural observation confirmed elongated prior beta grains in the building direction of both specimens (as-fabricated and heat-treated specimens). Along with such, the as-fabricated specimen only featured alpha'-martensite phase, while the heat-treated specimen featured alpha'-martensite and some alpha and beta phases. Compression tests carried out at room temperature gave yield strengths of 1365 and 1138 MPa for the as-fabricated and heat-treated specimens, respectively. Such values are similar or greater than those of commercial wrought materials. The compressive fracture strain significantly increased after heat treatment. There was a general tendency of reducing yield strength as compressive temperatures increased. At temperatures greater than 700 degrees C, the as-fabricated and heat-treated specimens achieved similar strength. Microstructural observation after deformation confirmed that the initial microstructure was retained up to temperatures of 500 degrees C. At 700 degrees C or greater, both specimens showed drastic microstructural evolution. (C) The Minerals, Metals & Materials Society and ASM International 2018.

키워드