Cellular structure mediated dislocation regulation in additively manufactured refractory high entropy alloy

Abstract

A Ti1.5Nb1Ta0.5Zr1Mo0.5 (TNTZM) refractory high entropy alloy (HEA) with a cellular structure was successfully fabricated by laser powder bed fusion (L-PBF). Compression testing and cyclic deformation testing results revealed that, in the cellular structure, the cell walls could store dislocations. Furthermore, the local chemical order (LCO) plays a crucial role in controlling dislocations within the cell wall region. The LCO not only facilitates dislocation slip but also generates additional lattice distortion upon stress-induced LCO destruction to enable dislocation pinning. This work offers novel insights into the microstructure of additively manufactured refractory HEAs and uncovers a distinct dislocation regulation mechanism.