Comparison of Microstructure Refinement in Wire-Arc Additively Manufactured Ti–6Al–2Sn–4Zr–2Mo–0.1Si and Ti–6Al–4V Built With Inter-Pass Deformation

Abstract The titanium alloy Ti–6Al–2Sn–4Zr–2Mo–0.1Si (Ti6242) has been deposited for the first time by a directed energy deposition process using wire and arc system— i.e., wire-arc additive manufacturing (WAAM)—with without inter-pass machine hammer peening, its microstructure investigated compared to more commonly used Ti–6Al–4V (Ti64). application of peening—where each added layer was deformed before deposition—successfully refined strongly textured, coarse, columnar β -grain structure that is seen in α + alloys, producing finer equiaxed grain with near-random texture. average diameter texture strength decreased peening pitch. When Ti6242 under identical conditions Ti64, switching feed in-situ, size across alloy-to-alloy transition reaching on 25 pct less than Ti64. A similar scale reduction also found -lath transformation microstructure. This comparatively greater refinement attributed dissimilar alloying elements present two materials; specifically, molybdenum, which lower diffusivity vanadium led slower growth during reheating as well