(1. 东北大学 材料与冶金学院, 沈阳 110004;
2. 北京航空材料研究院 铝镁研究室, 北京 100095)
摘 要: 通过拉伸测试和透射电镜分析, 研究时效温度和时间对2A97铝-锂合金组织和性能的影响。 结果表明： 经淬火后分别在135 ℃和155 ℃时效, 随着时效温度升高, 2A97合金强度升高, 达到峰值强度的时间提前, 延伸率降低； 随着时效时间延长, 合金屈服强度升高, 抗拉强度则先升高而后降低, 出现峰值强度, 延伸率下降； 当合金在155 ℃时效36 h, 获得最佳强度和塑性匹配, 抗拉强度为500 MPa, 屈服强度为413 MPa, 延伸率为7％； 随着时效温度升高, 合金组织中T1（Al2CuLi）相数量增加； 135 ℃的过时效合金显微组织主要为 θ′/θ″(Al2Cu) 相和δ′(Al3Li) 相, 155 ℃的时效合金显微组织主要为T1相、θ′/θ″相和δ′相。
关键字: 铝-锂合金; 2A97合金；时效; 显微组织; 力学性能
（1. School of Materials and Metallurgy, Northeastern University,
Shenyang 110004, China;
2. Research Laboratory of Al and Mg Alloys and Their Processing,
Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract: The effects of aging treatment on the microstructure and tensile properties of 2A97 Al-Li alloy, were investigated by tensile test and TEM. The results show that when the aging temperature increases, the tensile strength rises, meanwhile the tensile elongation decreases, and the aging kinetics at 155 ℃ is enhanced. When the aging time increases, σ0.2 rises continuously, and σb doesn't decrease before reaching the peak level, and the elongation decreases in overaging temper. σb, σ0.2 and δ5 of aged alloy at 155 ℃ for 36 h are 500 MPa, 413 MPa and 7%, respectively, which yields optimum relationship between ductility and strength. When the aging temperature increases, the number density of T1 phase increases, so the microstructure of alloy aged at 135 ℃ consists of θ′/θ″ and δ′ phases, and the microstructure of alloy aged at 155 ℃ mainly consists of θ′/θ″, δ′ and T1 phases.
Key words: aluminum-lithium alloy; 2A97 alloy; aging treatment; microstructure; mechanical property
