Influence of trace silicon addition on microstructure and properties of Ti6Al4V fabricated by wire arc additive manufacturing

To provide a pathway to improve the tensile properties of wire arc additive manufactured Ti6Al4V, the microstructures and properties of Ti6Al4V-0.1Si produced by the wire arc additive manufacturing were investigated in this study. It was demonstrated that the tensile strength of Ti6Al4V-0.1Si improved more than 100 MPa compared with traditional WAAM Ti6Al4V. The microstructures of WAAM Ti6Al4V and Ti6Al4V-0.1Si mainly consists of basket-weave structures but the width of the a-phase lamellae of Ti6Al4V-0.1Si is significantly lower. The added Si is solid-soluble on the a phase matrix of Ti6Al4V, which reduces the b phase transition temperature. Si as well produces the high growth restriction effect, then the a phase size is refined. The fine grain and solid solution strengthening are the main reasons for the increase in the strength of titanium alloy after adding trace Si. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).