Effect of vanadium contents on microstructure and mechanical properties of ti6alxv components produced by wire + arc additive manufacturing

Abstract

Wire + Arc Additive Manufacturing (WAAM) is an advanced manufacturing technology by inexpensive Gas Tungsten Arc Welding (GTAW) technology. Key microstructural features of the as-built WAAM alloy include large columnar grains, grain boundary colonies, and Heat Affected Zone (HAZ) banding, which generally leads to low ductility and anisotropy. In this study, Ti6AlxV (x = 0, 2, 4) alloys were prepared by WAAM, the effects of vanadium content on the microstructure, tensile properties and impact toughness were investigated. Irregularshaped, plate-like features without columnar grains and HAZ banding were obtained in Ti6Al alloy. Columnar grains were observed in Ti6Al2V alloy, and the grain size was further enlarged to more than ten millimeters by 4 mass% vanadium addition. With the increasing of vanadium content, a monotonic increase in yield strength and ultimate tensile strength can be observed, while the fracture strain and impact toughness changed in the opposite trend. Ti6Al and Ti6Al2Valloy exhibited better matching of strength, ductility and impact toughness compared with Ti6Al4V alloy.