温度及搅拌摩擦加工对AZ31镁合金力学性能的影响

Influence of temperature and friction stir processing on mechanical properties of magnesium alloy AZ31

在不同温度下对AZ31镁合金挤压型材实施了搅拌摩擦加工实验,利用光学显微镜和试样拉伸设备,研究了温度及搅拌摩擦加工对试样加工硬化率及力学性能的影响。研究表明:随着温度升高,母材和搅拌区材料的屈服强度和抗拉强度均减小,母材强度减小的较多;搅拌区材料的总伸长率和均匀伸长率均高于母材,温度达到100℃时,均达到最大值,分别为35%和33.5%;搅拌区材料室温及100℃的加工硬化率在较高应变量时仍能保持一定水平,而母材所有温度下的加工硬化率均随应变增大而大幅下降;母材的拉伸应变由非基面滑移和压缩孪晶主导,而搅拌区材料拉伸应变则转为由基面滑移和拉伸孪晶主导。

The friction stir processing（FSP） experiment was conducted for magnesium alloy AZ31 extrusion profile at different temperatures,and the influences of temperature and FSP on work hardening rate and mechanical properties of samples were investigated by means of optical microscope and sample stretching equipment.The results show that with the increase of temperature,the yield strength and ultimate tensile strength at the base material and the stirring zone material are reduced and that of the base material is reduced greatly.However,the total elongation and uniform elongation at the stirring zone material are higher than that of the base material,and the maximum values at 100 ℃ are up to 35% and 33.5% respectively.But the work hardening rate at the stirring zone material remains at a high level at room temperature and 100 ℃,and the work hardening rate at the base material decreases greatly with the increasing of stain at all temperatures.Furthermore,the tensile strain at the base material is dominated by the non-basal slip and compression twin crystals,while the tensile strain at the stirring zone material is dominated by the basal slip and tensile twin crystals.