Bridging processing and performance in Ti–6Al–4V: WAAM parameters and wear behavior across traditional and additive manufacturing routes

Wire-arc additive manufacturing (WAAM) has garnered attention in academia and industry and has huge potential because of its ability to fabricate complex geometry and economic viability compared to other metal additive manufacturing (MAM) processes. Its unparalleled design freedom, ability to manufacture near-net shaped components, less material wastage, ability to produce large components with a variety of materials, and flexibility in influencing material properties by varying the process parameters makes WAAM promising for industry. Ti–6Al–4V is the most prevalent titanium alloy because of its exceptional material properties and extensive application in aerospace industry, the marine sector, and bio-medical implants, among others. However, its use is limited due to its poor wear behavior due to oxidation, delamination, and spalling. Thus, it is crucial to improve the wear resistance of Ti–6Al–4V by surface engineering, manufacturing processes, and post-process treatments. In this review, we aim to provide a brief introduction to popular MAM processes, process parameters of WAAM, and path planning that influence the material properties and explore the wear behavior of the Ti–6Al–4V alloy in different environmental conditions, process parameters, and post-processing treatments. Due to the dearth of literature available on the wear behavior of the Ti–6Al–4V alloy manufactured using WAAM, the wear behavior of Ti–6Al–4V manufactured by L-PBF, SLM, and other conventional methods is reviewed. Additionally, this review paves the path of future exploration of the wear characteristics of the Ti–6Al–4V alloy manufactured by WAAM.