Process Optimization And Mechanical Properties Of Variable-plane-rolled Mg-3Al-1Zn Alloy

Magnesium and its alloys are widely used in aerospace,electronic information and automotive fields because of their light weight,high specific strength and high specific stiffness.The forming ability of magnesium alloy at room temperature is poor,and the traditional plastic forming method can not meet the needs of the industry application.Therefore,a new plastic forming method is of great significance to its development.variable-plane-rolled is a new rolling process.This process can improve the forming ability of magnesium alloy by changing the process of twin and texture evolution.The paper adopts the variable-plane-rolled process prepare the AZ31 magnesium alloy samples,and the variable-plane-rolled process is extended to sheet rolling process.The influence of temperature on the properties of the variable-plane-rolled magnesium alloys and the sheet produced by variable-plane-rolled process was studied.The relationship between microstructure and mechanical properties was also analyzed.The main results of this paper are as follows:(1)In the process of variable-plane-rolled at different temperatures,the mechanical properties of the surface decreased with the increase of the rolling temperature.The mechanical properties of AZ31 magnesium alloy show obvious tensile-compression asymmetry.Various types of twins exist in the AZ31 magnesium alloy samples produced by variable-plane-rolled process.The highest proportion of tensile twins was found in the sample.There was a significant double-peak basal texture in the AZ31 magnesium alloy samples produced by variable-plane-rolled process.(2)The fatigue properties of AZ31 magnesium alloy with variable-plane-rolled process are improved.Compared with the initial squeezing state AZ31 magnesium alloy,the fatigue limit is increased from 75MPa to 90MPa.The fatigue life curve of AZ31 magnesium alloy with variable-plane-rolled process can be divided into two stages:The twins play the leading role under the high stress state;Slip dominated under the low stress state.(3)The best properties of variable-plane-rolled sheet are achieved at 300 C.The yield strength is 276.1 MPa and the grain size is refined to 6.5?m.The texture of the variable-plane-rolled sheet is the single-peak feature.(4)The properties of variable-plane-rolled sheet and that of traditional rolled have their own advantages and disadvantages.The microstructure of variable-plane-rolled plate are even finer and more uniform,the anisotropy of mechanical properties is reduced,it's yield strength is higher.But the traditional rolling process is more convenient.