(中南大學 粉末冶金國家重點實驗室，長沙 410083)
摘 要: Al-Cu-Mg-Ag合金展示了比傳統(tǒng)Al-Cu及Al-Cu-Mg合金更加優(yōu)異的室溫與高溫力學性能，源于其主要強化相(Ω相)有較好的熱穩(wěn)定性。然而該合金的使用溫度仍然低于200 ℃，當溫度超過200 ℃時，Ω相的粗化速率急劇增加，容易發(fā)生共格失穩(wěn)而轉變?yōu)?I>θ相，從而降低合金的高溫力學性能。研究表明通過添加合適的稀土或過渡族元素可以有效地抑制Ω相的生長速率，提高Ω相的形核密度和熱穩(wěn)定性，從而提高合金的高溫力學性能。綜述了Ce、Yb及Sc元素對Al-Cu-Mg-Ag合金顯微組織與力學性能的影響，并探討了Ce、Yb及Sc元素提高Ω相熱穩(wěn)定性的機理。
關鍵字: Al-Cu-Mg-Ag合金；稀土；顯微組織；力學性能
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Al-Cu-Mg-Ag alloys exhibit much better mechanical properties than traditional Al-Cu and Al-Cu-Mg alloys at both room- and elevated temperatures because of the good thermal stability of the main strengthening phase (Ω phase). However, this type of alloys can only be used under 200 ℃. When the temperature is above 200 ℃, the coarsening speed of Ω phase increases dramatically, and Ω phase is very easy to lose coherent with the matrix and changes to θ phase, which substantially decreases the mechanical properties of the alloys at elevated temperature. It is shown that adding proper rare earth or transient elements can substantially inhibit the growth speed of Ω phase, increase the nucleation density and thermal stability of Ω phase, and thus improve the mechanical properties of Al-Cu-Mg-Ag alloys. The effects of Ce, Yb and Sc on the microstructures and mechanical properties of Al-Cu-Mg-Ag alloys were reviewed, and the mechanisms of the effects of Ce, Yb and Sc on the thermal stability of Ω phase were discussed.
Key words: Al-Cu-Mg-Ag alloy; rare earth; microstructures; mechanical properties
