Mg-9Zn—xAl合金的显微组织和力学性能

借助金相显微镜、扫描电镜、能谱分析仪、显微硬度计及电子万能试验机等研究了Mg-9Zn-xAl（x=2％、4％、6％）合金的显微组织和力学性能。试验结果表明：随着Al含量的增加，晶粒尺寸呈不断减小的趋势，合金中的第二相由断续状分布向连续网状转变；当Al含量为2％和4％时，合金主要由α-Mg基体相、τ-Mg32（Al，Zn）49相和MgZn相组成，当Al增加到6％时，合金主要由α-Mg基体相、τ-Mg32（Al，Zn）49相和少量Mg5Zn2A12相组成。抗拉强度随着Al含量的增加呈先增大后减小的趋势，当Al含量为4％时，抗拉强度为171MPa；伸长率和硬度随着Al含量的增加而逐渐增加，当Al含量为6％时，硬度为133HV。

Microstructure and Mechanics Properties of Mg-9Zn-xAl Alloys

The microstructure and mechanics properties of Mg-9Zn-xAl （x =2,4,6% ）alloys have been investigated by metallographic microscope, SEM, EDS, micro-hardness tester and electronic universal materials testing machine resulting in that with the increase of Al, the grain size of the alloy decreased and the distribution of the second phases in the alloys changed from quasti-eontinuous net to continuous net-work. When the content of Al was 2% and 4%, the alloys were composed of α-Mg, τ-Mg32 （Al,Zn）49 and MgZn phases. When the content of Al reached to 6%, the alloys were composed of α-Mg, τ-Mg32 Al, Zn ）49 and little Mg5Zn2Al2, phases. With the increase of Al, the tensile strength increased at first, then decreased. When the content of Al was 4%, the tensile strength got the maximum value of 171 MPa; The elongation and the hardness of alloys increasd gradually as the Al content increased. When the content of Al was 6%, the hardness reached the maximum value 133 HV.