(中南大學 材料科學與工程學院，長沙，410083)
摘 要: 用硬度測試、差熱分析(DSC)以及透射電鏡(TEM)研究Al-Cu-Mg-(Ag)合金時效過程中組織和性能的演變；根據(jù)不同升溫速率的DSC曲線，采用Kissinger法計算Ω相和θ′相的激活能，探討Ag對Al-Cu-Mg合金Ω相和θ′相析出行為的影響。結果表明：Al-Cu-Mg合金經(jīng)185 ℃時效后，時效硬化曲線呈雙階段硬化特征，生成少量Ω相；添加Ag后，合金的時效硬化能力顯著提高，經(jīng)170、185和200 ℃時效時，對應的峰值時效時間分別為10、5和2 h，峰值硬度隨著時效溫度的升高而下降；Ag能促進Ω相析出，使θ′相的激活能提高，從而抑制θ′相的 析出。
關鍵字: Al-Cu-Mg-(Ag)合金；Ω相；析出行為；微觀組織；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
