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采用金相显微分析、室温及250℃高温拉伸测试方法,研究了挤压比与预拉伸对2124-T351铝合金管材组织与力学性能的影响。研究结果表明,在502℃固溶240 min后,2124合金显微组织中仍存在少量残留的未溶过剩相。室温及250℃高温拉伸强度Rm及Rp0.2均随预拉伸率的增加呈先增大后减小趋势,且在预拉伸率为2.5%时达到强度峰值。壁厚22 mm管材的室温及高温拉伸强度Rm及Rp0.2均略高于壁厚30 mm管材。一方面原因是前者总体平均预拉伸率相对较高,管材残余内应力减小,强度值升高;另一原因是前者含Cu量稍高,在250℃高温拉伸时更容易析出S’(Al2Cu Mg)强化相。
The effects of extrusion ratio and pre-stretching on the microstructure and mechanical properties of 2124-T351 aluminum alloy pipe were studied by metallographic analysis, room temperature and high temperature tensile test at 250 ℃. The results show that there is still a small amount of residual undissolved excess phase in the microstructure of 2124 alloy after solution treatment at 502 ℃ for 240 min. The tensile strength Rm and Rp0.2 at room temperature and high temperature of 250 ℃ firstly increased and then decreased with the increase of pre-stretch ratio, and reached the peak value of strength when the pre-stretch ratio was 2.5%. Thickness of 22 mm pipe at room temperature and high temperature tensile strength Rm and Rp0.2 slightly higher than the wall thickness of 30 mm pipe. The reason is that on the one hand, the overall average pre-stretch ratio of the former is relatively high, the internal stress of the pipe decreases and the strength value increases; the other reason is that the former contains slightly higher Cu content and is more likely to precipitate S ’ (Al2CuMg) strengthening phase.