Developing a practice for the heat treatment of laser-powder bed fused Ti-6Al-2Sn-4Zr-2Mo-0.08Si alloy

Abstract

The laser-powder bed fusion (L-PBF) technique is employed to print cylindrical rods of near-α Ti-6Al-2Sn-4Zr-2Mo-0.08Si (Ti6242) alloy. The parts are printed using four scan speeds; 1000, 1200, 1400, and 1600 mm/s. Since the 1200 mm/s sample possesses the highest strength in the as-built condition, it is selected as the benchmark sample for heat treatment development. The kinetics of α to β phase transformation is employed in designing a two-step sub-transus heat treatment recipe. The mechanical properties and microstructure of both as-built and heat-treated parts are studied to elaborate on the process-microstructure-properties relationship and the effectiveness of the heat treatment recipe. In the next step, this recipe is applied to the other samples. The formulated heat treatment works effectively for all conditions and makes the final properties more uniform. This study shows the effectiveness of developing a heat treatment for one printing condition and extending it to other printing conditions.