Research On Microstructure And Mechanical Behavior Of ZK60 Magnesium Alloy

ZK60 magnesium alloy has a wide range of applications in the automotive,motorcycle,aerospace and weapon fields.In this paper,the tensile test of commercial rolled ZK60 magnesium alloy at different orientations and different loading rates was carried out.Combined with the microstructure analysis,the tensile mechanical behavior of the alloy after the original state,recrystallization annealing at 350 °C and corrosion treatment were researched.The main results are as follows:At the tensile rate of 0.01mm/s~0.1mm/s,the strength of the alloy increases with the increase of the tensile rate.When the tensile rate increases to 1mm/s,the strength of the alloy decreases,and the plasticity of the alloy decreases.The rate of elongation increases monotonically.At the same rate,the alloy shows lower tensile yield strength,higher plasticity and more obvious hardening phenomenon under transverse tension conditions.The decrease of yield strength of the alloy is mainly related to the orientation factor and grain refinement.The more obvious work hardening phenomenon is mainly the contribution of twin deformation.Compared with the original state,after 350 °C recrystallization annealing treatment,the yield strength and tensile strength of the alloy decreased,while the elongation and the area shrinkage rate increased remarkably.Because of the complete recrystallization of the alloy after annealing treatment,the crystal grains are refined,and the non-base surface slip is easy to be activated,so that the strength of the alloy decreases and the plasticity increases after annealing.After the corrosion treatment,the tensile mechanical behavior of the alloy has the same strain rate effect as the original alloy.However,in the range of 0.01mm/s~1mm/s loading rate,the strength and plasticity of the transverse direction of the alloy decrease with the increase of the loading rate.Under the same corrosion conditions,the tensile strength of the alloy is lower than that of the transverse direction at the loading rate of 0.01 mm/s.The tensile strength of the alloy is higher than that of the transverse direction in the range of 0.1 mm/s ~ 1 mm/s.In the range of 0.01mm/s~1mm/s loading rate,the transverse yield strength of the alloy is smaller than the longitudinal direction,but the plasticity is about 2~3 times of the longitudinal plasticity.