Experimental and simulation study on mechanical properties of ZK60 magnesium alloy after accumulative roll bonding

Abstract The mechanical properties of two- and four-layered wrought ZK60 Mg alloy sheets after two passes of accumulative roll bonding (ARB) with different reduction were studied and the microstructure were analyzed. The four-layered ZK60 sheets after ARB with 50% reduction demonstrate better strength-ductility combinations with yield strength of 223 MPa, ultimate tensile strength of 327 MPa, and total elongation of 23.7%, compared with the initial ZK60 of 222 MPa, 291 MPa and 10.0%, respectively. The average grain size of four-layered ARB ZK60 sheet is reduced from 21.8 μm of the initial sample to 4.4 μm. Using a micromechanical finite element model, the strain hardening behavior of ZK60 sheet was successfully predicted. The predictions were in good agreement with the experimental results. The simulation results reveals that the high performance of ZK60 sheets may be contributed by the lamella structure formed by the fine and coarse grains, which can avoid the local stress concentration and inhibit initiation and propagation of the microcracks. These findings provide a theoretical basis for the structural optimization design of ZK60 Mg alloys.