Paper Title
The Microstructure And Texture Of Selective Laser Melted Ti-6al-4v Alloy

Abstract
Selective laser melting (SLM) has been widely used to produce the high-density or porousTi-6Al-4Valloy due to its versatility. Unfortunately, the microstructure of SLM Ti-6Al-4V alloy is brittle α′-martensite phase, which sufficiently impair the ductility and toughness, because the cooling rate after SLM is as high as 1000ºC/s.To alleviate the brittleness of SLM Ti-6Al-4V, the aim of this study was to clarify the role of heat treatment at 750~1050 ºC in the microstructure of SLM Ti-6Al-4V alloy. The results indicate that minor β phase can be generated, and α′-martensite is decomposed into α+β mixed phases after heat treatment at 750 ºC. However, the original columnar grain remains in the microstructure. Moreover, the amount of β phase increases as the heat treatment temperature is raised. The ｛11-20｝ texture ofα phase still exists even after heat treatment at 950 ºC, as identified by the electron backscatter diffraction (EBSD) analysis. When the heat treatment temperature is increased to 1050 ºC, thecolumnar grain can transform to the equiaxed grain, and the microstructure after heat treatment is lamellar α+βmixture. Consequently, the microstructural anisotropy is thus much improved. Keywords - Selective laser melting;Ti-6Al-4V;microstructure; heat treatment, EBSD; texture