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为开发新型超高强铝锂合金,研究T8态时效处理的Mg、Ag、Zn复合微合金化Al-(3.2~3.8)Cu-(1.0~1.4)Li合金的显微组织及力学性能。结果表明,Li含量较低(1.0%)时,通过增加Cu含量来提高铝锂合金强度的作用有限,而同时增加Cu和Li含量则有利于其强度的明显提高。铝锂合金的主要强化相为大量细小弥散的T1(Al_2CuLi)相;同时,合金中还析出少量θ’(Al_2Cu)相及δ(Al_3Li)相,而且随时效过程的进行,其密度降低,甚至消失。Li含量较高时有利于δ’相及θ’相的形成,并可能导致形成少量S’(Al_2CuMg)相。另外,采用非固溶Cu、Li原子的总摩尔分数及其比例分析Cu、Li含量变化对合金强化效果及显微组织的影响。为获得超高强度的铝锂合金,一方面需提高Cu、Li原子的总摩尔分数,另一方面也应维持其较高比例。
In order to develop a new ultra-high strength Al-Li alloy, the microstructure and mechanical properties of Al, (3.2-3.8) Cu- (1.0-1.4) Li alloy with T8 aging treatment were studied. The results show that when the content of Li is low (1.0%), the effect of increasing the content of Cu by means of increasing the strength of the Al-Li alloy is limited. However, increasing the content of Cu and Li is beneficial to the improvement of the strength. The main strengthening phase of Al-Li alloy is a large number of small and diffusive T1 (Al2CuLi) phases. At the same time, a small amount of θ ’(Al2Cu) and δ (Al_3Li) phases are also precipitated in the Al-Li alloy and its density decreases with the aging process disappear. The higher Li content favors the formation of δ ’and θ’ phases and may lead to the formation of a small amount of S ’(Al 2 CuMg) phase. In addition, the effect of the content of Cu and Li on the strengthening effect and the microstructure of the alloy was analyzed by the total mole fraction of non-solution Cu and Li atoms and its proportion. In order to obtain ultra-high strength Al-Li alloys, the total mole fraction of Cu and Li atoms should be increased on the one hand and the higher proportion should be maintained on the other hand.