双级时效对变形2A12铝合金组织与性能的影响

采用拉伸试验机、扫描电镜、金相显微镜等仪器,研究了双级时效对变形2A12铝合金组织与性能的影响。结果表明:初始态2A12铝合金经495 ℃×12 h均匀化退火处理后,组织趋于均匀,析出较多弥散T相。双级时效对镦粗变形铝合金抗拉强度的提升相比单级时效有更明显的作用,且双级时效的二级时效温度和时间是提高强度的主导因素,二级时效温度不宜超过200 ℃,保温时间不宜超过6.5 h,否则会导致材料过烧,强度下降。因此2A12铝合金最佳热处理工艺为495 ℃×1 h固溶+100 ℃×2 h+180 ℃×6.5 h时效,经该工艺处理后,晶粒细化,第二相强化作用增强,材料综合性能优异。

Effect of two-stage aging on microstructure and properties of deformed 2A12 aluminum alloy

Effect of two-stage aging on the microstructure and properties of deformed 2A12 aluminum alloy were studied by using tensile testing machine, scanning electron microscope, metallographic microscope and other instruments. The results show that the microstructure of the alloy tends to be uniform after homogenized and annealed at 495 ℃×12 h, and more dispersed T phases are precipitated. The two-stage aging has more significant effect on improving the tensile strength of upset deformed aluminum alloy than the single-stage aging, and the temperature and time of the two-stage aging are the main factors for improving the strength. The second-stage aging temperature can't exceed 200 ℃, and the time should not exceed 6.5 h, otherwise it will cause over-melted of the material and decrease the strength.Therefore, the best heat treatment process for 2A12 aluminum alloy is 495 ℃×1 h solid solution, 100 ℃×2 h+180 ℃×6.5 h aging. After this process, the grains are refined, the secondary phase strengthening is enhanced, and the comprehensive properties of the alloy are excellent.