热处理Mg-9Y-1Cu合金的组织结构及力学性能

Microstructure and Mechanical Properties of Heat Treated Mg-9Y-1Cu Alloy

采用金相显微镜、扫描电子显微镜(SEM)、XRD等方法研究了热处理Mg-9Y-1Cu合金热处理后的组织结构,利用万能材料试验机测试样品的力学性能,用SEM研究了材料的断裂机理。结果表明,T6处理样品晶粒内部析出层片状14H结构LPSO相。经过挤压,T1合金晶粒明显减小,晶界增多,在晶间及晶粒内部弥散分布着细小第二相。挤压后人工时效样品(T5合金)晶粒长大,且析出的第二相数量有所增多。T6合金屈服强度和抗拉强度分别达到97 MPa和193 MPa。T1合金细化的晶粒和弥散分布第二相使得合金的综合力学性能显著提高,达到商用AZ系列镁合金的强度。T5合金伸长率有所下降,而强度变化不明显。

The microstructure of heat-treated Mg-9 Y-1 Cu alloy was studied by metallographic microscope, scanning electron microscope(SEM) and XRD. The mechanical properties of the samples were tested by tensile testing machine, and the fracture mechanism was studied by SEM. The results show that the lamellar 14 H LPSO is precipitated from the grains of T6 samples. After extrusion, the grain size decreases obviously, and the fine second phase disperses in the intergranular and internal grains. The grains of T5 alloy grow up and the amount of second phase increases. The yield strength and tensile strength of T6 alloy are 97 MPa and 193 MPa, respectively. The refined grains and dispersed second phase of T1 alloy significantly improve the mechanical properties of the alloy.The strength of T1 alloy reachs of commercial AZ series Mg alloy. The elongation of T5 alloy decreased, but the change of strength was not obvious.