Microstructure and mechanical properties of as-built and heat-treated electron beam melted Ti-6Al-4V

This paper investigates the effect of post-deposition heat treatment on porosity, microstructure, and mechanical properties of Ti-6Al-4V produced via an Electron Beam Melting process. Samples were studied in the conditions of as-built and heat treated at 920 degrees C and 1030 degrees C. The as-built samples were characterised by columnar beta grains consists of alpha+beta microstructure with Widmanstatten and colony morphologies were found. Heat treatment resulted in increased alpha lath width. The yield strength and ultimate tensile strength was greater in the as-built condition than wrought material. Porosity re-growth occurred after heat treatment but it did not affect the tensile properties. Greater ductility after heat treatment was attributed to the larger alpha lath width which increases effective slip length.