Inhibiting grain boundary cracking in laser additively-manufactured MoNbTaVTiCu refractory complex concentrated alloys by tuning the Cu/Ti content

Abstract

Refractory complex concentrated alloys (RCCAs) have been proposed for extreme service applications due to their microstructural stability and excellent mechanical properties over a wide temperature range. However, printing MoNbTaV-based RCCAs by laser additive manufacturing can be challenging on account of the severe solidification cracking that occurs along grain boundaries (GBs), leading to poor mechanical strength. In this brief report, we describe a crack-free MoNbTaVTi_xCu_y RCCA produced through compositional adjustment that leverages a Cu-Ti phase to suppress GB cracking. Printed and annealed specimen exhibited both good mechanical strengths and  thermal conductivities.