Multi-type dislocation substructure evolution in a high-strength and ductile duplex high-entropy nanocomposites

Abstract

Developing energy-efficient and scalable microstructural solutions that enable both an intrinsically high strength and high ductility has always been a pursuit in materials science. We have used a spark plasma sintering synthesis strategy to efficiently fabricate a duplex high-entropy nanocomposite composed of the high-entropy nano-intermetallic precipitates and high-entropy nanoscale solid-solution domains. The high-entropy nanocomposite with spontaneous phase separation accompanied by the reorganization of high-entropy components achieves the minimal lattice misfit (∼0.07%) integration of the high-entropy nano-intermetallic precipitates with the high-entropy nanoscale solid-solution domains. The resulting high-entropy nanocomposite exhibited a high tensile strength (i.e., a fracture strength close to 1.7 GPa) and large plasticity (i.e., a uniform elongation close to 20%). The duplex nanostructure in our high-entropy nanocomposite described herein had multi-type dislocation substructure evolution during deformation, including dislocation planar slip, coplanar dislocation arrays, dislocation walls, microbands, and stacking faults in solid-solution domains. Because of the dominance of multiple hardening modes, our high-entropy nanocomposite could ensure that the plasticity was large enough to maintain a high strength. Our findings break through the challenge of the tradeoff between efficiency and superb performance in preparing nanostructured materials, thereby significantly facilitating the development of high-performance nanocomposites and advanced nanostructured materials.