Selective laser annealing of cold-rolled high-entropy alloy to defeat strength-ductility trade-off

The long-lasting strength-ductility paradox exists for metallic materials. Architecting heterogeneous structures offers the possibility to overcome this challenge. In this study, we have devised an approach to precisely customize heterogeneous structures by utilizing a focused high-energy laser beam to selectively laser-anneal (SLA) cold-rolled parts. Given the extensive application potential of high-entropy alloys (HEAs), Al0.1CoCrFeNi HEA was taken as a model material. By generating heterogeneous laminated structures, the optimized SLA-3 HEA achieves a synergy of yield strength (~805.8 MPa) and uniform elongation (~27.9%), attributed to dual-scale asynchronous deformations—between original and recrystallized grains at the microscale, and between soft and hard lamellae at the macroscale. These deformations induce significant back-stress strengthening and sustained strain hardening. Furthermore, this strategy was successfully applied to energy-absorbing square tubes, realizing superior specific energy absorption and a low initial peak force. These findings demonstrate the potential of the present strategy to create metallic materials with deliberately controlled heterogeneous microstructures and excellent performance for practical applications. This study controls heterogeneous structure in a high-entropy alloy using a focused high-energy laser beam to selectively laser anneal (SLA) cold-rolled parts, achieving a yield strength of 805 MPa and uniform elongation of 28%.