Effect of substrate preheating on the texture, phase and nanohardness of a Ti-45Al-2Cr-5Nb alloy processed by selective laser melting

摘要

The crystallographic texture, phase composition and evolution, and nanohardness of a Ti-45Al-2Cr-5Nb alloy processed by selective laser melting (SLM) at various substrate preheating temperatures were investigated. The alpha(2) phase decreases whereas the gamma and B-2 phases increase with increasing preheating temperature, and the relationship in orientation between B-2, alpha(2) and gamma phases is described as follows: (11 (2) over bar0) alpha(2)//(111) gamma//(111) B-2. The SLM-processed TiAl alloy shows much higher nanohardness than its traditional casting counterpart, which increases with the increase of preheating temperature. The findings would be a valuable reference for fabricating TiAl components with acceptable texture, phase compositions and nanohardness by SLM. (C) 2016 Elsevier Ltd. All rights reserved.