Influence Of Texture On Mechanical Properties In AZ System Magnesium Alloys

As lightest structural metal materials,magnesium and its alloys have many excellent performance,such as high specific strength and good electrical conductivity.However,magnesium alloy always exhibit poor workability and ductility at room temperature due to its hexagonal close packed?HCP?crystal structure,which limits the activation of slip systems.Therefore,investigating the influence of texture on mechanical properties from micro perspectives has an important guiding significance for promoting the practical value of magnesium products.This research selects AZ system magnesium alloys as primary experimental materials and uses different microscopy characterization methods such as electron backscatter diffraction?EBSD?and optical microscopic?OM?,systematically investigated the connection between texture component and factors of Hall-Petch relation in as-extruded AZ31 Mg alloys,study the influence of waste heat rolling and asymmetric reduction rolling on the microstructure and mechanical properties of AZ31 and AZ91 Mg alloys.The main results are as follows:?1?The Hall-Petch relations of uniaxial tension and compression in as-extruded AZ31Mg alloy are very different,and the discrepancy of texture component also has great impact on factors of Hall-Petch relation.Besides,there has a large possibility that more than one deformation mechanisms are activated during plastic deformation process of Mg samples.If considering all these effects in the calculation of the friction stress?₀ by using weighted method,the theoretical value will be more accurate.According to the experimental results,the value of the grain size sensitivity k rises with the increase of texture intensity.?2?Compared with symmetric rolling,large number of twinning is activated in AZ31sheets due to the lower deformation temperature during the second pass of waste heat rolling.The microstructure of material is significantly refined because of the twin boundary provides more favorable positions for the nucleation of recrystallized grains.And thus,the mechanical property of AZ31 Mg alloy is obviously improved.?3?On the basis of symmetric rolling,asymmetric reduction rolling introduces a shear stress along the thickness of rolled sheet through changing the reduction of upper and lower layers and the flow velocity of each layer,finally the texture intensity of AZ91 was weakened.Besides,the AZ91 sheet processed by asymmetric reduction rolling has more fine and homogenous microstructure and better mechanical property.