Mechanical properties and deformation mechanism of lightweight Al 0.5 NbTi 3 VZr 0.5 high‐entropy alloy via laser surface melting process

Abstract The lightweight refractory high‐entropy alloys (LRHEAs) are considered as next‐generation high‐performance weaponry matrix material. In this work, we employ the laser surface melting (LSM) method to ulteriorly optimize surface mechanical properties of Al 0.5 NbTi 3 VZr 0.5 matrix HEA, where the phase structures, mechanical properties and deformation mechanism of as‐cast and LSM‐treated HEAs have been investigated. The LSM process eliminates tanglesome intermetallic Zr 5 Al 3 structures and effectively improves the mechanical properties of as‐cast HEA. The sample after 2000 W LSM treatment exhibits the superior comprehensive mechanical properties, its tensile elongation, microhardness of remelt zone and volume wear loss are 31.6%, HV 809.6 and 296.4 × 10 −3 mm 3 , representing the advancement of 85.9%, 180.1% and 64.6% compared to that of as‐cast HEA sample, respectively. Additionally, the deformation behavior of the as‐cast sample involves solid phase transformation, stacking faults and deformation twinnings. The deformation mechanism of as‐cast Al 0.5 NbTi 3 VZr 0.5 HEA is transformation‐induced plasticity (TRIP) and twinning‐induced plasticity (TWIP), the classical Burgers mechanism of BCC → HCP solid phase transformation is revealed, which obeys [111] BCC ∥ [1120] HCP . As for the 2000 W treated sample, the deformation mechanism is mainly TWIP as the stacking fault energy enhancement evidenced by the presence of cross‐slip dislocations after LSM process.