Flow and fracture study for ZK60 alloy at dynamic strain rates and different loading states

Abstract

This paper presents an on-going study of light-weight alloy ZK60 magnesium. The uniaxial tensile tests were carried out with strain rate range of (0.0001–1000)/s−1 and with different stress states. Elemental data was identified through an iteration process using finite element analysis. The modified Johnson-Cook (J-C) model was calibrated to describe the flow stress as a function of strain and strain rate. The modified Mohr-Coulomb (M-C) model, considering the effects of strain, stress state and strain rate, was proposed with satisfactorily determined parameters. Compared by the original J-C fracture model, the modified M-C fracture model tracks the fracture behavior more accurately. To complement the macroscale fracture information, fractography reveals the fracture and deformation mechanism in microscale. The agreements between the simulations and tests further confirmed that the modified J-C material model and the modified M-C material model can give a precise estimate of the mechanical and fractural behavior of the ZK60 alloy.