时效处理和La含量对AZ91合金组织和力学性能的影响

来源期刊：金属学报2011年第6期

论文作者：王社斌 祁小叶 张金玲 刘璐 许并社

文章页码：743 - 750

关键词：AZ91镁合金； 时效； 力学性能； 显微组织

Key words：AZ91 magnesium alloy； aging； mechanical property； microstructure

摘    要：借助XRD,SEM,EDS和显微硬度仪等分析测试手段,研究了时效处理和La含量对真空精炼的AZ91合金显微组织和力学性能的影响.结果表明:时效处理可以使第二类β相大量析出,且β相呈不连续层片状沿晶界两侧分布.随La含量的增加,β相的尺寸逐渐减小,而α相的尺寸则呈现先减小后增加的趋势.铸态和时效态试样的力学性能参数均随La含量的增加呈现出先增加后减小的趋势.时效态试样的抗拉强度、屈服强度、延伸率和Vickers硬度分别比铸态试样提高12.65%,16.85%,13.71%和37.24%.当La含量达到0.1648%时,抗拉强度、屈服强度、延伸率和Vickers硬度分别达到276 MPa,208 MPa,13.85%和132HV.

Abstract: The effects of aging treatment and La content on the microstructures and mechanical properties of AZ91 magnesium alloys were investigated by XRD,SEM,EDS and microhardness meter. The results showed that a great number of β-phases were precipitated and distributed along the grain boundaries after aging treatment.As the content of La increased,the grain size of β-phase decreased gradually,while α-phase decreased first and then increased.The mechanical properties of as-cast and aged specimens increased first and then decreased as the content of La increased.The tensile strength, yield strength,elongation and Vickers hardness of aged magnesium alloys were increased by 12.65%, 16.85%,13.71% and 37.24%,respectively.When the content of La was 0.1648%,the tensile strength, yield strength,elongation and Vickers hardness achieved 276 MPa,208 MPa,13.85% and 132 HV, respectively.