(1. 湖南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410082；
2. 北京航空材料研究院，北京 100095)
摘 要: 采用硬度測(cè)試、拉伸性能測(cè)試、DSC分析和透射電鏡(TEM)等方法研究不同時(shí)效制度對(duì)2A97鋁鋰合金組織和性能的影響。結(jié)果表明：采用165 ℃人工時(shí)效時(shí)，峰值強(qiáng)度最高，但其塑性也最差，且達(dá)到峰值的時(shí)間長(zhǎng)達(dá)60 h；200 ℃人工時(shí)效時(shí)，達(dá)到峰值的時(shí)間縮短為6 h，而其峰值強(qiáng)度和塑性均很差；(200 ℃, 6 h)+(165 ℃, 6 h)雙級(jí)時(shí)效優(yōu)化后，可獲得比200 ℃峰時(shí)效更高的強(qiáng)度，其抗拉強(qiáng)度為545 MPa，只比165 ℃峰時(shí)效強(qiáng)度低11 MPa，伸長(zhǎng)率卻提高至7.1%，且時(shí)效時(shí)間比165 ℃峰時(shí)效時(shí)縮短了48 h。2A97鋁鋰合金峰時(shí)效狀態(tài)下的析出相有T1(Al2CuLi)相、θ′相和一定量的σ(Al5Cu6Mg2)相。根據(jù)不同升溫速率下的DSC曲線，采用Kissinger法求得T1相的析出激活能為75.9 kJ/mol。綜合分析可知，采用(200 ℃, 6 h)+(165 ℃, 6 h)雙級(jí)時(shí)效可以得到比單級(jí)時(shí)效更加優(yōu)異的綜合性能。
關(guān)鍵字: 2A97鋁鋰合金；時(shí)效；顯微組織；力學(xué)性能；激活能
（1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:The effect of aging treatment on the microstructure and mechanical properties of 2A97 Al-Li alloy during artificial aging was studied by hardness measurement, tensile test, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results indicate that 2A97 alloy obtains the highest strength, but its elongation is relatively low when aged at 165 ℃ for 60 h; when it is aged at 200 ℃, only 6 h is needed to achieve peak aging, whereas the peak strength and elongation are both poor; when the alloy is aged at (200 ℃, 6 h)+(165 ℃, 6 h), the aging time of which is 48 h less than that of single aging treatment when peak values are obtained, while the tensile strength is 545 MPa, only 11 MPa less than that of single aging treatment, and the elongation increases to 7.1%. The T1(Al2CuLi) phase, θ'''' phase and σ(Al5Cu6Mg2) phase are the major precipitates in 2A97 alloy. According to the DSC curves at various heating rates, the activation energies of T1 phases by Kissinger method is 75.9 kJ/mol. To sum up, the (200 ℃, 6 h)+(165 ℃, 6 h) double aging treatment can endow the alloy with more excellent comprehensive performance than single aging system.
Key words: 2A97 Al-Li alloy; aging; microstructure; mechanical property; activation energy
