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研究热处理参数对Ti-5Al-2Sn-2Zr-4Mo-4Cr合金显微组织的影响及其等轴组织、双态组织和魏氏组织的室温拉伸力学性能和拉伸断口形貌。获得3种典型显微组织的热处理温度分别为830、890和920°C,并保温30 min后炉冷。炉冷时,初生α相体积分数随热处理温度的升高而减小,在热处理温度为830、890和920°C时,初生α相的体积分数分别为45.8%、15.5%和0;空冷时,初生α相体积分数的变化规律类似。升高热处理温度和炉冷均有利于次生α相的析出和长大。等轴组织具有良好的综合拉伸性能,其抗拉强度、屈服强度、伸长率及断面收缩率分别为1035 MPa、1011 MPa、20.8%和58.7%;双态组织的屈服强度和伸长率略低于等轴组织的屈服强度和伸长率;魏氏组织的韧性差、屈服强度低,但抗拉强度高达1078 MPa。等轴组织和双态组织的室温拉伸断口呈韧窝断裂,塑性较好;魏氏组织的室温拉伸断口中韧窝断裂和晶间断裂共存,塑性较差。
The effects of heat treatment parameters on the microstructure of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy and its tensile properties were investigated at room temperature. The heat treatment temperatures of the three typical microstructures were 830, 890 and 920 ° C, respectively, and then cooled in the furnace for 30 min. When the furnace is cold, the volume fraction of primary α phase decreases with the increase of the heat treatment temperature. The volume fraction of primary α phase is 45.8%, 15.5% and 0 at the heat treatment temperatures of 830, 890 and 920 ° C, respectively. The changes of primary α-phase volume fraction were similar. Elevated heat treatment temperature and furnace cooling are conducive to the secondary α precipitation and growth. The equiaxed structure has good comprehensive tensile properties, and the tensile strength, yield strength, elongation and reduction of area are 1035 MPa, 1011 MPa, 20.8% and 58.7%, respectively. The yield strength and elongation of the bimodal structure are slightly Lower than the yield strength and elongation of the equiaxed tissue; Wei Tissue toughness, yield strength is low, but the tensile strength of up to 1078 MPa. The tensile fracture at room temperature of equiaxed and bimodal structures was dimpled and ruptured at room temperature. The ductile fracture and intergranular rupture of Westen’s microstructure in tensile fracture at room temperature coexisted with poor ductility.