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研究了热压缩、热轧制和后续轧制退火处理对Ti-6Al-4V合金显微组织和拉伸性能的影响。热压缩实验在温度800~1075°C和应变速率0.001~1s-1下进行,得到了流变曲线与加工过程参数之间的关系。然后,样品在温度800~1070°C和恒应变速率2s-1下进行2道次热轧制,总变形量为75%。热轧后,样品分别在870°C和920°C下保温热处理2h,随后空冷。在β相区的热轧导致粗大的β相冷却时转变为马氏体相,而在α/β两相区的热轧会导致生成部分球化的α相组织。后续的热轧处理能使在两相区部分球化的α相得以完成球化,然而,在β相区轧制的样品会导致马氏体结构被破坏。拉伸实验表明,随着轧制温度从两相区升高到单相区,合金的强度及伸长率会显著降低。升高热处理温度会降低两相区轧制合金的强度性能,而在β相区轧制合金的强度会得到提高。
The effects of hot compression, hot rolling and subsequent rolling annealing on the microstructure and tensile properties of Ti-6Al-4V alloy were investigated. The hot compression experiment was carried out at a temperature of 800 ~ 1075 ° C and a strain rate of 0.001 ~ 1s-1. The relationship between the rheological curve and the processing parameters was obtained. Then, the sample was hot-rolled by 2 passes at a temperature of 800 to 1070 ° C and a constant strain rate of 2 s-1 for a total deformation of 75%. After hot rolling, the samples were heat-treated at 870 ° C and 920 ° C for 2h, respectively, and then air-cooled. Hot rolling in the β-phase region results in the transformation into the martensite phase upon coarse β-phase cooling, whereas hot rolling in the α / β two-phase region results in the formation of partially spheroidized α-phase structures. Subsequent hot rolling treatment can make the α-phase partially spheroidized in the two-phase region to complete spheroidization. However, the sample rolled in the β-phase region will cause the martensite structure to be destroyed. Tensile tests show that as the rolling temperature increases from the two-phase zone to the single-phase zone, the strength and elongation of the alloy decrease significantly. Increasing the heat treatment temperature decreases the strength properties of the rolled alloy in the two-phase region, whereas the strength of the rolled alloy in the β-phase region is increased.