Process optimization of high entropy alloys by laser additive manufacturing

Abstract

Aerospace components and their coatings are required to possess excellent surface properties over a wide temperature range. Stainless steels, titanium, nickel superalloy, and more recently high entropy alloys (HEAs) have been used to improve the exterior properties of these components. In this study, AlTiCrFeCoNi and AlCoCrFeNiCu HEAs were successfully fabricated using laser additive manufacturing to produce coatings on an A301 steel base plate. The influence of the laser parameters (laser power and scan speed) on the microstructure and hardness properties were also investigated. The results revealed that coatings homogeneously adhered to the baseplate. The optimum processing parameters for both alloys with defect-free structures at a preheat temperature of 400°C, were at 1200-1600 W at 8-12 mm/s with the layers composed of both face centredcubic (FCC) and body centred-cubic (BCC) phases. The laser parameters affected the quality and hardness properties of the alloys. The results showed that optimizing the laser parameters achieved by preheating temperature invariably improved the performance of the alloys with potential coatings and structural applications.