(1. 北京航空材料研究院 結(jié)構(gòu)鋼、功能材料與熱處理工藝研究室，北京 100095；
2. 南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063)
摘 要: 采用THERMECMASTOR-Z熱模擬實(shí)驗(yàn)機(jī)對(duì)2D70鋁合金進(jìn)行等溫恒應(yīng)變速率壓縮實(shí)驗(yàn)，基于加工圖技術(shù)研究該合金在320~530 ℃和0.001~70.0 s-1范圍內(nèi)的變形特性，并優(yōu)化出適宜的變形熱力學(xué)參數(shù)范圍。結(jié)果表明：在熱變形過程中，隨著真應(yīng)變的增加，合金的變形失穩(wěn)區(qū)域增大。當(dāng)應(yīng)變速率較大(≥1.0 s-1)時(shí)，變形多處于失穩(wěn)區(qū)域；當(dāng)變形溫度低于350 ℃、應(yīng)變速率大于1.0 s-1時(shí)，微觀組織中出現(xiàn)了裂紋；當(dāng)變形溫度高于500 ℃、應(yīng)變速率大于1.0 s-1時(shí)，易出現(xiàn)機(jī)械失穩(wěn)；而在變形溫度低于350 ℃、應(yīng)變速率低于0.1 s-1時(shí)，微觀組織中出現(xiàn)楔形裂紋。綜合加工圖以及微觀組織觀察結(jié)果，獲得了試驗(yàn)參數(shù)范圍內(nèi)熱變形的最佳工藝參數(shù)，變形溫度為370~460 ℃、應(yīng)變速率為0.004~0.1 s-1。
關(guān)鍵字: 2D70鋁合金；加工圖；變形行為；微觀組織
（1. Department of Structure Steel, Functional Materials and Metal Heat Treatment Technology,
Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The isothermal compression tests with constant strain rate for aluminum alloy 2D70 were conducted by THERMECMASTOR-Z hot simulator. The hot deformation behaviors in the temperature range of 320-530 ℃ and the strain rate range of 0.001-70.0 s-1 were investigated. Then, the processing maps under these deformation conditions were constructed and the deformation thermomechanical parameters were then optimized based on the generated processing maps. The results show that the flow instability zone increases with true strain increasing during the hot deformation process. Otherwise, when the strain rate is higher than 1.0 s-1, most of the deformation behavior is located at the flow instable zone. Under this condition, the domain of flow localization appears at the temperature lower than 350 ℃ and mechanical instability exhibits at the temperature higher than 500 ℃. While, when the strain rate is lower than 0.1 s-1 and the temperature is lower than 350 ℃, the wedge cracking can be found. On the base of the experimental results including processing map and microstructure, the optimum deformation thermomechanical parameter ranges of aluminum alloy 2D70 can be confirmed to the temperature range of 370-460 ℃ and the strain rate range of 0.004-0.1 s-1.
Key words: aluminum alloy 2D70; processing map; hot deformation behavior; microstructure
