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针对航空用高强Al-4.2Cu-1.4Mg铝合金,研究了退火温度对微观组织结构、力学性能和疲劳裂纹扩展速率的影响。采用金相显微镜、扫描电镜和能谱分析手段对合金的微观组织和析出相种类进行了分析。结果表明:退火温度从380℃提高到440℃后,T3态板材中的晶粒尺寸不断细化,第二相Al2CuMg和Al2Cu的体积分数逐渐减少,因此疲劳裂纹扩展速率呈下降趋势。另外,随着中间退火温度的升高,成品板材的拉伸强度有少量降低,而伸长率则有所提高。
Aiming at the high strength Al-4.2Cu-1.4Mg aluminum alloy for aviation, the effects of annealing temperature on microstructure, mechanical properties and fatigue crack growth rate were studied. The microstructures and precipitated phases of the alloy were analyzed by metallographic microscope, scanning electron microscope and energy spectrum analysis. The results show that when the annealing temperature is increased from 380 ℃ to 440 ℃, the grain size in the T3 plate is continuously refined, and the volume fraction of the second phase Al2CuMg and Al2Cu gradually decreases. Therefore, the fatigue crack growth rate decreases. In addition, with the intermediate annealing temperature increases, the tensile strength of the finished plate a small amount of reduction, while the elongation is increased.