Al-Zn-Mg-Cu系超高强度铝合金的研究现状与发展趋势

Current Status and Future Directions of Ultrahigh Strength Al-Zn-Mg-Cu Aluminum Alloys

分析了近年来超高强度Al-Zn-Mg-Cu系铝合金的成分设计、工艺优化、显微组织分析、力学性能测试及微量元素的作用,对今后的发展动向提出了一些新的看法:采用传统铸造技术得到的铝合金,Zn含量的最大值在8wt％左右,抗拉强度低于700MPa;采用喷射成形技术,Zn含量最大值能够超过12wt％,同时抗拉强度可达800MPa以上,大大提高了铝合金的强度;超高强度铝合金的固溶强化相主要为MgZn_2相;经回归时效处理(RRA)后,合金同时具有T6的强度和T7X的抗应力腐蚀性能;微量元素对超高强度铝合金的组织和性能具有显著的影响。

Designing of composition, optimization of processing, analysis of microstructure, test of property and the effects of trace elements in ultrahigh strength aluminum alloys(Al-Zn-Mg-Cu) are reviewed in the paper,and some new views on their future prospects are brought forward. Aluminum alloys manufactured by conventional casting method with Zn content less than 8wt% have a tensile strength lower than 700MPa,whereas other alloys obtained by spray forming with Zn content more that 12wt% can achieve a tensile strength up to 800MPa,improving strength of aluminum alloys greatly. The solid-solution hardening phase in ultrahigh strength aluminum alloys is MgZn2. The aluminum alloys can combine the strength of T6 alloy with the stress corrosion cracking resistance of T7X alloy through retrogress and reageing(RRA) treatment. The effects of trace elements on microstructure and property of ultrahigh strength aluminum alloys is obvious.