(1. 中国船舶重工集团公司 第七二五研究所，洛阳 471039；
2. 有研科技集团有限公司 有色金属材料制备加工国家重点实验室，北京 100088)
摘 要: 采用等温热变形实验，结合TEM分析，研究了Al-Cu-Li合金热变形过程的动态软化机制和析出相动态演变规律。基于Zener-Hollomon参数(Z)、变形温度(T)、热激活参数和微观组织分析，明确了合金热变形过程的动态软化机制。结果表明：当lnZ＞51.70，t＜420 ℃时，以螺位错的交滑移和刃位错攀移为主要软化机制；当47.10＜lnZ≤51.70，t≥380 ℃，以螺位错交滑移、三维位错网络的脱缠以及部分位错脱钉为主要软化机制，有部分动态再结晶出现；当lnZ≤47.10，t≥420 ℃，以动态回复和动态再结晶为主要软化机制。合金热变形过程(340~500 ℃)T1(Al2CuLi)相的动态析出与细化规律为：340~460 ℃保温阶段有粗大T1相析出，340~420 ℃变形阶段T1相动态析出且被细化。细化源自两个方面：1) 保温阶段析出的粗大T1相因变形被碎化和回溶；2) 原始晶界和变形过程引入的大量位错、亚晶界等为T1相的析出提供大量异质形核位置，导致T1的细小析出。t＞460 ℃时，没有T1相析出。热变形过程β′(Al3Zr)相和含Mn相始终稳定存在，δ′(Al3Li)相在淬火过程即可析出。
关键字: Al-Cu-Li合金；热变形；动态回复；再结晶；动态析出
（1. Luoyang Ship Material Research Institute, Luoyang 471039, China;
2. State Key Laboratory of Nonferrous Metals and Processes, GRINM Group Co., LTD., Beijing 100088, China）
Abstract:The dynamic softening mechanism and the dynamic evolution of the precipitate phase in the thermal deformation process of Al-Cu-Li alloy were studied by isothermal thermal deformation experiment and TEM analysis. Based on the Zener-Hollomon parameter (Z), deformation temperature (t), thermal activation parameters and microstructure analysis, the dynamic softening mechanism of the alloy during the thermal deformation was clarified. The results show that, when lnZ>51.70 and T<420 ℃, the main softening mechanism is cross-slip of screw dislocation and climbing of edge dislocation; when 47.10<lnZ<51.70 and t≥380 ℃, the cross-slip of screw dislocation，detachment of three-dimensional dislocation network and particle dislocations depinning are the main softening mechanism, and some dynamic recrystallization occurs; when lnZ≤47.10 and t≥420 ℃, the dynamic recovery and dynamic recrystallization are the main softening mechanism. Dynamic precipitation and refinement of T1 phase (Al2CuLi) of the alloy during hot deformation (340-500 ℃) were studied systematically. The rule of dynamic precipitation and refinement of T1 phase is as follows: the coarse T1 phase precipitation occurs at the holding stage of 340-460 ℃, and the T1 phase is precipitated and refined dynamically at the deformation stage of 340-420 ℃. The refinement of T1 phase are derived from two aspects. One is that, the coarse T1 phase precipitated in holding stage is broken and dissolved during the hot deformation processing. The other is that, the original grain boundaries, a large number of dislocations and subgrain boundaries introduced during the hot deformation provide a large amount of heterogeneous nucleation site for the T1 phase, which leads to the fine precipitation of T1. When the deformation temperature is higher than 460 ℃, without precipitation of T1. The β′ phase (Al3Zr) and Mn-containing phase always keep stable existence during the hot deformation. The δ′ phase (Al3Li) can precipitate in the quenching process.
Key words: Al-Cu-Li alloy; hot deformation; dynamic recovery; dynamic recrystallization; dynamic precipitation
