Study On The Hot Deformation Rate Equation And Dynamic Recrystallization Of Magnesium Alloy

Magnesium alloy is the lightest metal of structure materials with a series of unique advantages,such as high specific strength, high specific stiffness, good electromagnetic shielding ability and casting performance, easy recycling, excellent noise damping and shock-absorbing characteristics.It is a green material with development potential.Deformation strain rate equation is the basic equation and the mathematical expression of the deformation mechanism.In this paper, the strain rate equations of AZ31 magnesium alloy were studied at different temperatures and stress under tensile test .The results show that: when the temperature is greater than or equal to 240℃, there is a critical stress, the equations are of different forms when the stress is greater than or less than the critical stress,and the critical stress was determined by experiments.Dynamic recrystallization is an popular structure often occurs during deformation of magnesium alloy , which has a major impact on the performance of the material after deformation .The critical strain of dynamic recrystallization of the magnesium alloy were determined by both empirical and a single parameter method respectively.The effect of deformation parameters especially the section shrinkage rate of the samples on the size and fractions of recrystallized grains were analyzed.The texture changes before and after tensile test of the magnesium alloy were studied with X-ray diffraction analysis. The extruded AZ31 magnesium alloy has the base texture before test, that the base surface is parallel to the extrusion direction.The texture of magnesium alloy is still basal texture after high temperature tensile deformation, however,a rotation occurred on the cylinder.This discovery is providing an experimental basis for further analysis of the deformation mechanism of magnesium alloy.