(中南大学 材料科学与工程学院，长沙，410083)
摘 要: 用硬度测试、差热分析(DSC)以及透射电镜(TEM)研究Al-Cu-Mg-(Ag)合金时效过程中组织和性能的演变；根据不同升温速率的DSC曲线，采用Kissinger法计算Ω相和θ′相的激活能，探讨Ag对Al-Cu-Mg合金Ω相和θ′相析出行为的影响。结果表明：Al-Cu-Mg合金经185 ℃时效后，时效硬化曲线呈双阶段硬化特征，生成少量Ω相；添加Ag后，合金的时效硬化能力显著提高，经170、185和200 ℃时效时，对应的峰值时效时间分别为10、5和2 h，峰值硬度随着时效温度的升高而下降；Ag能促进Ω相析出，使θ′相的激活能提高，从而抑制θ′相的 析出。
关键字: Al-Cu-Mg-(Ag)合金；Ω相；析出行为；微观组织；激活能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effect of Ag on the microstructure and mechanical properties of Al-Cu-Mg-(Ag) alloy during artificial aging was studied by Vickers hardness measurement, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The analysis of DSC curves at various heating rates was carried out to evaluate the activation energies of Ω and θ′ phases by Kissinger method. The effect of Ag on the precipitation behavior of Ω and θ′ phases in Al-Cu-Mg alloy was investigated. The results show that the aging hardening curve of Al-Cu-Mg alloys is of two-stage hardening at 185 ℃ with a small amount of Ω phase precipitated. When Ag is added to Al-Cu-Mg alloy, the aging hardening ability is greatly improved. The aging time of Al-Cu-Mg-Ag alloy corresponding to the peak value of hardening is 10, 5 and 2 h, respectively, when the alloy is aged at 170, 185 and 200 ℃, while the peak hardness decreases with the increase of the aging temperature. The addition of Ag in Al-Cu-Mg alloy promotes the formation of Ω phase and increases the activation energy of θ′ phase, resulting in the suppression precipitation of θ′ phase.
Key words: Al-Cu-Mg-(Ag) alloy; Ω phase; precipitation behavior; microstructure; activation energy
