(1. 中南大學 輕合金研究院，長沙 410083；
2. 中南大學 高性能與復雜制造國家重點實驗室，長沙 410083)
摘 要: 采用單軸恒應力蠕變試驗、電子背散射衍射(EBSD)和透射電子顯微鏡(TEM)技術等實驗手段，研究了Al-Cu-Li合金厚板的不均勻組織特征對其蠕變時效成形過程的影響。結果表明：厚向不均勻組織的差異性表現(xiàn)出明顯不同的蠕變變形行為，靠近中心層的特征組織具有更高的蠕變量和更快的初始蠕變速率；厚板特征組織的晶粒尺寸與蠕變變形之間無確定的相關性，而位錯運動是影響蠕變量的主要因素；晶粒尺寸在蠕變時效前后變化微小，但蠕變時效后小角度晶界比例存在不同程度的提高。此外，厚板不同特征組織會影響蠕變時效過程中強化相T1的析出行為，靠近中心層的特征組織在蠕變過程中會形成更多的位錯纏結，促使T1相大量析出和致密分布。
關鍵字: Al-Cu-Li合金；厚板；蠕變時效成形；微觀組織
（1. Research Institute of Light Alloy, Central South University, Changsha 410083, China;
2. State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha 410083, China）
Abstract:The effect of inhomogeneous structure on creep aging process of Al-Cu-Li alloy thick plate was studied by uniaxial constant stress creep test, electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) techniques. The results show that the difference of the thick-direction inhomogeneous structures exhibits obvious different creep deformation behavior, and the characteristic structure near the center layer has a higher creep and a faster initial creep rate. There is no definite correlation between the grain size of the characteristic structure of the thick plate and the creep deformation, and the dislocation movement is the main factor affecting the creep. The grain size changes slightly before and after creep aging, but the proportion of small-angle grain boundaries increases to a varying degree after creep aging. In addition, the different characteristic microstructures of the thick plate could affect the precipitation behavior of the strengthening phase T1 during the creep aging process. The characteristic structure near the center layer forms more dislocation entanglements during the creep process, which promotes a large number of precipitation and dense distribution of T1 phase.
Key words: Al-Cu-Li alloy; thick plate; creep aging forming; microstructure
