(1. 中南大學(xué) 材料科學(xué)與工程，長沙 410083；
2. 中南大學(xué) 輕合金研究院，長沙 410083；
3. 中南大學(xué) 高性能復(fù)雜制造國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 采用掃描電鏡、透射電鏡、常溫拉伸、斷裂韌性、疲勞裂紋擴(kuò)展速率等測試方法對比研究蠕變時(shí)間、自然時(shí)效及人工時(shí)效對Al-Cu-Mg合金蠕變成形后的力學(xué)性能、疲勞裂紋擴(kuò)展性能和顯微組織的影響。結(jié)果表明：不同蠕變成形時(shí)間對合金的常溫力學(xué)性能影響較小，抗拉強(qiáng)度和屈服強(qiáng)度的波動幅度均在4%以內(nèi)；相比于人工時(shí)效狀態(tài)，合金在自然時(shí)效狀態(tài)下綜合性能更好；試樣經(jīng)413 ℃、12 h蠕變成形后，再進(jìn)行T4時(shí)效處理得到最佳的綜合性能，通過該實(shí)驗(yàn)條件，成形試樣不僅具有較高的力學(xué)性能，而且有較高的延展性和疲勞裂紋擴(kuò)展性能。
關(guān)鍵字: Al-Cu-Mg合金；斷裂韌性；疲勞裂紋；擴(kuò)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
