Deformation Behavior And Texture Evolution Of AZ31 Magnesium Alloy Based On Strong Basal Texture

Magnesium alloy as one of the lightest metal structural materials,because of its high specific strength and recyclability and other characteristics,in the military,aerospace and other industrial fields have a very broad development prospects,by the majority of researchers as the 21 st century resources and environmental sustainability of the green materials.The unique dense row hexagonal crystal structure of magnesium alloys usually leads to a strong basal weave and poor ductility and formability,and the redevelopment of magnesium alloy materials is greatly limited.The main factors affecting the deformation texture of magnesium alloys are the deformation conditions.The deformation conditions and initial texture determine the activation of the deformation mechanism,and the activation of the deformation mechanism in turn affects the evolution of the micro texture.Therefore,studying the deformation mechanism,mechanical properties,twinning variants and texture evolution of magnesium alloys during plastic deformation has great potential and broad applications for strengthening or improving its mechanical properties and forming process properties.Using computer simulation method to predict the properties of materials has become the focus of current research.The viscoplastic self-consistent(VPSC)model also considers slip,twin system and material anisotropy,and has been successfully applied to the study of large deformation behavior of polycrystalline materials.Based on this,the VPSC model was used to simulate the mechanical properties of magnesium alloy under different deformation conditions,and the activation of deformation mechanism and texture evolution law of magnesium alloy during deformation were predicted in real-time.Combined with the experimental and simulation results,the plastic deformation behavior of AZ31 magnesium alloy with strong basal texture is studied from the perspective of micro deformation mechanism.The real stress-strain curves of AZ31 magnesium alloy were obtained by three-way tensile and compressive experiments,and the hardening parameters applicable to the plastic deformation behavior of magnesium alloy were obtained by fitting the stress-strain curves with a modified VPSC model.The effects of secondary deformation mechanisms(prismatic <a> slip,pyramidal<c+a> slip and {10(?)1} compression twinning)on the plastic deformation process of magnesium alloy were numerically studied.It was found that secondary deformation mechanism have a certain effect on the macroscopic stress and microtexture during plastic deformation of magnesium alloy.Therefore,in order to simulate and predict the plastic deformation process of magnesium alloy more accurately,the secondary deformation mechanism should be embedded in VPSC model.Based on the established VPSC model,the activition of deformation mechanism and texture evolution of magnesium alloy during tensile and compressive plastic deformation were simulated and predicted.The obvious difference of initial texture leads to the obvious anisotropy of different deformation behaviors by affecting the activition of deformation mechanism.Initial texture plays an important role in texture evolution by influencing the priority of deformation mechanism.The microstructure results show that the microstructure difference between samples with different initial texture is mainly due to the number and morphology of {10(?)2} tensile twinning,which is mainly due to the obvious difference of initial texture.The correctness and rationality of the proposed method are verified by electron backscatter diffraction(EBSD).The {10(?)2} twinning phenomenon in AZ31 magnesium alloy under three dimensional compression was studied by using EBSD technique and Schmidt factor calculation method.The equivalent Schmid factor algorithm under rolling condition is improved,and the Schmid factor algorithm under 45° direction is established.Combined with the microstructure characterization,it is found that the selection mechanism of {10(?)2} tensile twins follows the Schmid rule and is affected by the strain compatibility.