(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 采用维氏硬度、光学显微镜、双臂电桥电阻及透射电子显微镜等手段，研究普通时效与应力时效时，外加应力对Al-Cu-Mg-Ag合金时效析出行为的影响。结果表明：外加应力会降低Al-Cu-Mg-Ag合金的时效硬化速率，减小峰值硬度和延长欠时效时间；外加应力能够促进Al-Cu-Mg-Ag合金中θ′相的析出，抑制Ω相的析出和长大；在外加应力的影响下，Ω相产生应力位向效应，且应力位向效应的产生主要在Ω相的形核阶段形成。
关键字: Al-Cu-Mg-Ag合金；应力时效；应力位向效应；微观组织
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:Comparing the normal aging and stress aging, the effects of external stress on the aging precipitation behavior of Al-Cu-Mg-Ag alloy were studied by Wicker hardness test (HV), optical microscopy (OM), two-bridge electric-resistivity test and transmission electron microscopy (TEM). The results show that the external stress during aging decreases the aging process of Al-Cu-Mg-Ag alloy and the hardness of peak aging, and prolongs the time of underaging stage. The external stress can enhance the precipitation of θ′ phase and retard the precipitation and growth of Ω phase. With the effects of the external stress, the preferential oriented precipitation of Ω phase is observed, which mainly forms in the nucleation stage of Ω phase.
Key words: Al-Cu-Mg-Ag alloy; stress aging; stress-orientation effect; microstructure
