(1. 中南大学 材料科学与工程，长沙 410083；
2. 中南大学 轻合金研究院，长沙 410083；
3. 中南大学 高性能复杂制造国家重点实验室，长沙 410083)
摘 要: 采用扫描电镜、透射电镜、常温拉伸、断裂韧性、疲劳裂纹扩展速率等测试方法对比研究蠕变时间、自然时效及人工时效对Al-Cu-Mg合金蠕变成形后的力学性能、疲劳裂纹扩展性能和显微组织的影响。结果表明：不同蠕变成形时间对合金的常温力学性能影响较小，抗拉强度和屈服强度的波动幅度均在4%以内；相比于人工时效状态，合金在自然时效状态下综合性能更好；试样经413 ℃、12 h蠕变成形后，再进行T4时效处理得到最佳的综合性能，通过该实验条件，成形试样不仅具有较高的力学性能，而且有较高的延展性和疲劳裂纹扩展性能。
关键字: Al-Cu-Mg合金；断裂韧性；疲劳裂纹；扩展速率
（1.School of Material Science and Engineering, Central South University, Changsha 410083, China;
2. School of Light Alloy Research, Central South University, Changsha 410083, China;
3. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:Using scanning electron microscopy (SEM), transmission electron microscopy (TEM), room temperature tensile, fracture toughness and fatigue crack propagation rate and other test methods, the effects of natural aging and artificial aging on the mechanical properties, fatigue crack growth performance and the microstructure after creep time of Al-Cu-Mg alloy creep forming were investigated. The results show that the different creep forming time has less influence on the room temperature mechanical properties of alloy with the fluctuate of tensile strength and yield strength within 4%. Compared with the artificial aging, the comprehensive performance of alloy under natural ageing state is better. The best comprehensive performance of sample is obtained under the experimental conditions of (413 ℃, 12 h) creep forming and T4 aging treatment. Through the experimental conditions, the forming sample has not only high mechanical properties, but also high ductility and fatigue crack propagation performance.
Key words: Al-Cu-Mg alloy; fracture toughness; fatigue crack; propagation rate
