(1. 中國船舶重工集團(tuán)公司 第七二五研究所，洛陽 471039；
2. 有研科技集團(tuán)有限公司 有色金屬材料制備加工國家重點(diǎn)實(shí)驗(yàn)室，北京 100088)
摘 要: 采用等溫?zé)嶙冃螌?shí)驗(yàn)，結(jié)合TEM分析，研究了Al-Cu-Li合金熱變形過程的動態(tài)軟化機(jī)制和析出相動態(tài)演變規(guī)律。基于Zener-Hollomon參數(shù)(Z)、變形溫度(T)、熱激活參數(shù)和微觀組織分析，明確了合金熱變形過程的動態(tài)軟化機(jī)制。結(jié)果表明：當(dāng)lnZ＞51.70，t＜420 ℃時，以螺位錯的交滑移和刃位錯攀移為主要軟化機(jī)制；當(dāng)47.10＜lnZ≤51.70，t≥380 ℃，以螺位錯交滑移、三維位錯網(wǎng)絡(luò)的脫纏以及部分位錯脫釘為主要軟化機(jī)制，有部分動態(tài)再結(jié)晶出現(xiàn)；當(dāng)lnZ≤47.10，t≥420 ℃，以動態(tài)回復(fù)和動態(tài)再結(jié)晶為主要軟化機(jī)制。合金熱變形過程(340~500 ℃)T1(Al2CuLi)相的動態(tài)析出與細(xì)化規(guī)律為：340~460 ℃保溫階段有粗大T1相析出，340~420 ℃變形階段T1相動態(tài)析出且被細(xì)化。細(xì)化源自兩個方面：1) 保溫階段析出的粗大T1相因變形被碎化和回溶；2) 原始晶界和變形過程引入的大量位錯、亞晶界等為T1相的析出提供大量異質(zhì)形核位置，導(dǎo)致T1的細(xì)小析出。t＞460 ℃時，沒有T1相析出。熱變形過程β′(Al3Zr)相和含Mn相始終穩(wěn)定存在，δ′(Al3Li)相在淬火過程即可析出。
關(guān)鍵字: Al-Cu-Li合金；熱變形；動態(tài)回復(fù)；再結(jié)晶；動態(tài)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
