(1. 東北大學(xué) 材料與冶金學(xué)院, 沈陽 110004;
2. 北京航空材料研究院 鋁鎂研究室, 北京 100095)
摘 要: 通過拉伸測試和透射電鏡分析, 研究時效溫度和時間對2A97鋁-鋰合金組織和性能的影響。 結(jié)果表明： 經(jīng)淬火后分別在135 ℃和155 ℃時效, 隨著時效溫度升高, 2A97合金強(qiáng)度升高, 達(dá)到峰值強(qiáng)度的時間提前, 延伸率降低； 隨著時效時間延長, 合金屈服強(qiáng)度升高, 抗拉強(qiáng)度則先升高而后降低, 出現(xiàn)峰值強(qiáng)度, 延伸率下降； 當(dāng)合金在155 ℃時效36 h, 獲得最佳強(qiáng)度和塑性匹配, 抗拉強(qiáng)度為500 MPa, 屈服強(qiáng)度為413 MPa, 延伸率為7％； 隨著時效溫度升高, 合金組織中T1（Al2CuLi）相數(shù)量增加； 135 ℃的過時效合金顯微組織主要為 θ′/θ″(Al2Cu) 相和δ′(Al3Li) 相, 155 ℃的時效合金顯微組織主要為T1相、θ′/θ″相和δ′相。
關(guān)鍵字: 鋁-鋰合金; 2A97合金；時效; 顯微組織; 力學(xué)性能
DAI Sheng-long2, LIU Chang-sheng1
（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
