The effect of accumulative roll bonding on the microstructure and properties of AX10/ZK60 layered heterogeneous magnesium alloy

ABSTRACT Magnesium alloys with low density and high specific strength have broad aerospace and transportation prospects, but monolithic ones fail to meet complex service demands; layered composites have become key research directions via advantage complementarity. In this study, the accumulative roll bonding (ARB) technique was used to fabricate AX10/ZK60 layered heterogeneous composites, with systematic exploration of ARB passes influence on their microstructure evolution and mechanical properties. Results show that as ARB passes increase, the composite strength and toughness continuously rise, ultimately achieving integrated high strength and toughness. At 6 ARB passes (ARB-6), it attains a tensile strength of 282 MPa, yield strength of 258 MPa, elongation at break of 17.2 %, and specific strength of 162.8 MPa/(g/cm3). Microstructural characterization reveals continuous grain refinement with more ARB passes; fine dynamically recrystallization (DRX) at layered interfaces significantly strengthen the composite. The formed “layered bimodal structure” extends crack propagation paths, and increased interlayer interfaces from more passes enhance crack propagation resistance, improving plastic deformation capacity. Quantitative evaluation of yield strength contributions from grain boundaries (GBs), precipitation, solid solution, and dislocation strengthening shows total contributions of 231.06 MPa (ARB-1), 243.29 MPa (ARB-3), and 274.95 MPa (ARB-6), with GBs and dislocation strengthening as the predominant mechanisms. This work sheds new light on the synergistic strengthening-toughening mechanism of layered bimodal structures in heterogeneous magnesium alloys, providing a fundamental reference for the design and fabrication of other high-performance multi-component metal matrix composites.