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

摘要

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 alpha' martensite with minority lamellar alpha + beta and it results in a reasonable hardness and tensile strength. All alpha' martensites could transform to alpha + beta phase after 900 degrees C-4 h-furnace cooling and 1200 degrees 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.