Lattice distortion enabling enhanced strength and plasticity in high entropy intermetallic alloy

Abstract

Intermetallic alloys have traditionally been characterized by their inherent brittleness due to their lack of sufficient slip systems and absence of strain hardening. However, here we developed a single-phase B2 high-entropy intermetallic alloy that is both strong and plastic. Unlike conventional intermetallics, this high-entropy alloy features a highly distorted crystalline lattice with complex chemical order, leading to multiple slip systems and high flow stress. In addition, the alloy exhibits a dynamic hardening mechanism triggered by dislocation gliding that preserves its strength across a wide range of temperatures. As a result, this high-entropy intermetallic circumvents precipitous thermal softening, with extensive plastic flows even at high homologous temperatures, outperforming a variety of both body-centered cubic and B2 alloys. These findings reveal a promising direction for the development of intermetallic alloys with broad engineering applications. Intermetallics are traditionally characterised by their inherent brittleness due to a lack of sufficient slip systems and the absence of strain hardening. Here authors show that a single-phase distorted high entropy B2 intermetallic alloy displays notable strength and plasticity at room temperature, along with stable plastic flow at high homologous temperatures.