Process control of laser melting deposition for AlMo0.5NbTa0.5TiZr refractory high-entropy alloys and its impact on forming quality

Abstract

AlMo0.5NbTa0.5TiZr is a novel class of lightweight refractory high-entropy alloy with exceptional strength at elevated temperatures. It has garnered significant attention as a high-temperature structural material in recent times. In this research, laser melting deposition technology was used to manufacture AlMo0.5NbTa0.5TiZr RHEAs. The impact of process variables on the forming quality of LMD-shaped AlMo0.5NbTa0.5TiZr RHEAs was examined using the single-factor approach. According to the study, the laser power had the most significant effect on the penetration depth during the single-pass forming process. In contrast, the scanning speed had the most significant effect on the deposited layer's height. In multi-pass forming, under the appropriate overlap ratio (50 % to 45 %), laminar flow heat and mass transfer characteristics were observed between passes, resulting in a lower surface waviness of the deposited layer samples and no obvious pores or other defects within the deposited layer. Preheating the substrate can reduce the number of cracks and pores in the multi-layer three-dimensional samples of AlMo0.5NbTa0.5TiZr RHEAs.