Screening of Refractory High-Entropy Alloy Solidification Behavior Through Laser Glazing

Abstract

The high-temperature strength of refractory high-entropy alloys (RHEAs) limits viable thermomechanical processing routes; thus, their behavior in solidification-based processes such as casting and laser powder bed fusion additive manufacturing is a primary limitation in realizing their use in extreme environment applications. The present research investigates the differences in hot cracking behavior among four refractory high-entropy compositions that show inconsistencies in their predicted cracking susceptibility according to different indicators, including the freezing range, Clyne cracking susceptibility criterion, and Kou cracking susceptibility index. Hot cracking behavior is assessed using laser glazing at two laser powers and eight different laser scan speeds for arc-melted alloy pairs. Cracking susceptibility differences and melt pool behavior are quantified and compared for key alloy pairs and assessed in the context of the strengths and limitations of cracking susceptibility indicators.