固相合成法制备Al2O3亚微米颗粒增强AZ31复合材料及强化机理

Fabrication of submicron size Al2O3/AZ31 composite prepared by solid-phase synthesis and its strengthening mechanism

采用固相合成方法制备Al2O3亚微米颗粒增强AZ31镁基复合材料,利用OM、SEM、TEM对Al2O3/AZ31镁基复合材料进行组织观察,利用维氏硬度仪、电子万能拉伸试验机对Al2O3/AZ31镁基复合材料进行力学性能测试。结果表明:经过固相合成后,Al2O3亚微米颗粒均匀的分布在AZ31基体中,通过对基体位错运动的钉扎作用,使该区域的位错密度增加,促进动态再结晶形核,复合材料的晶粒被显著细化。Al2O3/AZ31复合材料的力学性能随着Al2O3亚微米颗粒含量的增加而提高,当Al2O3颗粒含量为2%时,复合材料的力学性能达到最大值,其硬度、抗拉强度、屈服强度和伸长率分别为83HV、302 MPa、203 MPa和8.15%。

The solid-phase synthesis was used to prepare the submicron size Al2O3/AZ31 composite. Its microstructure and mechanical properties were characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and electron universal strength tester. The results show that the submicron size Al2O3 particles are uniformly distributed in AZ31 magnesium matrix after solid-phase synthesis. Al2O3 particles increase the dislocation density by pinning the dislocation motion of the matrix, promoting the dynamic recrystallization nucleation, resulting in refined grains of the composites. Meanwhile, the mechanical properties of the composites increase with the increase of the content of submicron size Al2O3 particles. When the content of Al2O3 particles is 2%, the mechanical properties of the composite reach the maximum. The hardness, tensile strength, yield strength and elongation are 83 HV, 302 MPa, 203 MPa and 8.15%, respectively.