In situ alloying from powder blends enables processing of high copper content Ti-6Al-4V by laser powder bed fusion

Abstract Adding copper (Cu) to titanium (Ti) alloys or Ti-6Al-4V offers the potential to tailor microstructure and material properties, but previous studies report processing challenges for Cu contents above 5 wt%. In this work, Ti-6Al-4V powder was blended with pure Cu powder to investigate in situ alloying at 10, 15, and 20 wt% Cu using laser powder bed fusion. A systematic process parameter study was conducted, using identical parameters for all compositions, to evaluate the influence of Cu content on processability, density, and microstructural evolution. High relative densities (up to 99.99 %) and homogeneous, fine-grained microstructures were achieved, demonstrating that in situ alloying with Cu contents up to 20 wt% is feasible. While 10 wt% Cu could be processed robustly under all conditions, higher Cu contents showed an increased tendency for cracks. For 15 wt% and 20 wt% Cu, at least one set of parameters for each composition yielded a dense, crack-free sample. The microstructure was analyzed in detail using SEM to investigate the markedly different morphologies, while XRD was employed to identify the formed phases, including α- and β-Ti as well as Ti₂Cu. Mechanical properties were evaluated using Vickers hardness measurements (HV1) to compare the effect of Cu additions. EDS analysis confirmed chemical homogeneity across all blends. This work highlights the potential of powder blending combined with laser powder bed fusion to explore new Ti-6Al-4V–xCu compositions beyond previously reported limits.