机械零部件用高强镁合金加工工艺与组织性能研究

针对Mg-Gd-Y合金塑性较差的问题,研究了固溶态和不同温度锻造加工态高强Mg-Gd-Y合金的组织与性能。结果表明,固溶态Mg-Gd合金的晶粒尺寸不均匀,平均尺寸约225μm;当锻造加工温度为440℃和410℃时,合金中第二相的数量较多,大量弥散分布的第二相的存在可以抑制动态再结晶的形成;随着锻造加工温度的降低,Mg-Gd合金的抗拉强度和屈服强度呈现逐渐升高的趋势,在锻造加工温度为470℃时,Mg-Gd合金的断后伸长率达到最大值19.2%,降低锻造加工温度至440℃和410℃时,断后伸长率反而有所降低;固溶态Mg-Gd合金的拉伸断口呈现脆性断裂的特征;锻造加工温度为500℃的拉伸断口呈现混合断裂特征,而锻造加工温度为410℃、440℃和470℃时Mg-Gd合金的断口都呈现为韧性断裂特征。

Study on Processing Technology and Microstructure and Properties of High Strength Magnesium Alloy for Mechanical Parts

In order to solve the problem of poor plasticity of Mg-Gd-Y alloy,the microstructure and properties of Mg-Gd-Y alloys of solid solution state and forged at different temperatures were studied.The results showed that the grain size of solid solution Mg-Gd alloy was not uniform,and the average size was about 225 μm;when the forging temperatures were 440 ℃ and 410 ℃,the number of second phases in the alloys were large,and a large number of dispersed second phases could inhibit the formation of dynamic recrystallization;with the decreasing of forging temperature,the tensile strength and yield strength of Mg-Gd alloy showed increasing trend;when the forging temperature was 470 ℃,the elongation of Mg-Gd alloy reached the maximum value of 19.2％,and when the forging temperatur reduced to 440 ℃ and 410 ℃,the elongation decreased;the tensile fracture surface of the solid solution Mg-Gd alloy showed the feature of brittle fracture,and the tensile fracture surface at the temperature of 500 ℃ was mixed fracture,while the fracture surfaces of the Mg-Gd alloys were characterized by ductile fracture at 470 ℃,440 ℃ and 410 ℃.