Microstructure and mechanical properties of as-built and heat-treated Ti-6Al-4V alloy prepared by cold metal transfer additive manufacturing

Abstract

Ti-6Al-4V titanium alloy components fabricated by cold metal transfer additive manufacturing (CMTAM) have increasingly shown great potential in aerospace applications in recent years. In this work, the microstructure and mechanical properties of the as-built and heat-treated Ti-6Al-4V wall have been investigated, respectively. The results show that the as-built Ti-6Al-4V wall has the microstructure consisting of acicular α’ martensite with minority lamellar α+β and it results in a reasonable hardness and tensile strength. All α’ martensites could transform to α+β phase after 900 °C-4 h-furnace cooling and 1200 °C-2 h-furnace cooling heat treatment. By using the former or the latter heat treatments, a higher hardness or better ductility can be obtained for the CMTAM-fabricated wall, respectively. While, the tensile strength of the heat-treated sample is considerably lower than that of the as-built sample.