(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 通過常規(guī)拉伸性能測試、掃描電鏡(SEM)和透射電鏡(TEM)觀察，研究少量Mg、Ag、Zn多元微合金化對一種新型Al-Cu-Li合金微觀組織與拉伸性能的影響。結(jié)果表明：在T6、T8時效態(tài)下，該合金的抗拉強(qiáng)度(σb)和屈服強(qiáng)度(σ0.2)均大于不含Mg、Ag、Zn的另外3種合金的，而伸長率(δ)相差較小。其主要強(qiáng)化析出相為大量的T1相、部分θ′相和少量的S′相。在T6時效態(tài)下，Mg、Ag的同時存在大大促進(jìn)T1相和S′相的析出，顯著增加合金強(qiáng)度；Mg、Zn的同時添加也促進(jìn)T1相和S′相的析出，使合金強(qiáng)度在一定程度上得到提高。Mg元素微合金化的強(qiáng)化效果最強(qiáng)，同時添加Ag和Zn或單獨(dú)添加Ag或Zn均能增強(qiáng)其強(qiáng)化效果；無Mg存在條件下，添加Ag、Zn對合金的強(qiáng)化效果較小。在T8時效態(tài)下，時效前的預(yù)變形形成的大量位錯成為T1相的形核點(diǎn)，使合金形成細(xì)小、密集和均勻彌散分布的T1相，削弱了Mg、Ag、Zn元素對合金時效析出過程的影響。
關(guān)鍵字: Mg；Ag；Zn；Al-Cu-Li合金；拉伸性能；微觀組織
（School of Materials Science and Engineering, Central South University, Changsha 410083，China）
Abstract:The effects of Mg, Ag and Zn multi-alloying on tensile properties and microstructure of a new Al-Cu-Li alloy were investigated by means of tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the tensile strength (σb) and yield strength (σ0.2) of the new Al-Cu-Li alloy are higher than those of the three alloys without Mg, Ag and Zn, respectively, while the elongation (δ) is almost the same in T6 and T8 temper. The main strengthening phases are plenty of T1 phase, part of θ′ phases and a little of S′ phase. In T6 temper, the additions of Mg and Ag accelerate the precipitation of T1 and S′ phase which improves the strength prominently. Mg and Zn also accelerate the precipitation of T1 and S′ phases, which improve the strength to some extent. The microalloying of Mg shows the strongest strengthening effect, while adding both of Ag and Zn or adding Ag or Zn separately can enhance the strengthening effect of Mg. Without the presence of Mg, the additions of Ag and Zn have little effect on the strengthening. In T8 temper, the predeformation before aging forms plenty of dislocations which become the precipitation sites of T1 phase, making finer, dense and uniform T1 phase in the matrix, which weakens the effects of Mg, Ag and Zn on the aging behavior of the new Al-Cu-Li alloy.
Key words: Mg; Ag; Zn; Al-Cu-Li alloy; tensile property; microstructure
