Effects of Heat Treatment on High Temperature Mechanical Property and Corrosion Resistance of Hastelloy X Manufactured by Selective Laser Melting

Abstract

In previous studies, the microstructure, mechanical properties and corrosion resistance of Hastelloy X fabricated by selective laser melting (SLM) have been investigated; however, it is hoped that heat treatment will effect on its properties. Therefore, this study is to discuss heat treatment effect on Hastelloy X fabricated by SLM. It is interestingly found that fracture strain greatly increases with heat treatment, and the yield ratio decreases, which demonstrates the material is more reliable. High temperature tensile behavior is discussed; it is worth mentioning that not only fracture strain of the HT sample increases greatly at 550∘C in comparison with SLM sample, but also ultimate tensile strength increases from 632 MPa to 639 MPa; the results show that the mechanical property can be improved at medium and high temperature by heat treatment. The corrosion resistance of HT sample deteriorates slightly, which can be explained by Cr-rich precipitates. In conclusion, the material after heat treatment is suitable for applications requiring high mechanical reliability and medium and high temperature occasions, but it is not befitting for corrosive environments.