(西北工業(yè)大學 航空學院，西安 710072)
摘 要: 建立了塑性流動本構模型，對Al3003-H12、2219-T87、7050-T7451、2024-T351和LY12-cz 5種典型的鋁合金在應變率從10−4 /s到8 000 /s，初始溫度從77 K到800 K以及真實應變超過0.50條件下進行系統(tǒng)實驗，并對塑性流動行為進行分析。結果表明：這些鋁合金材料具有應變率效應；鋁合金材料應變率敏感性可歸于短程障礙對熱激活位錯運動的影響；在200~600 K時，這些材料存在第三類動態(tài)應變時效現象。基于熱激活位錯運動機制，推出一個物理概念的本構模型，比較得出的模型預測結果和實驗結果一致，可方便用于工程應用。
關鍵字: 鋁合金；塑性流動；應變率；動態(tài)應變時效；本構模型
several typical aluminum alloys
（School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:In order to evaluate the strain rate sensitivity and set up the constitutive model of aluminum alloys, five types of aluminum alloys as Al3003-H12, 2219-T87, 7050-T7451, 2024-T351 and LY12-cz were systematically tested under strain rate range of 10−4−8 000 /s, initial temperature of 77−800 K and the true strain exceeding 0.50. The plastic flow behavior of these materials was also analyzed. The results show that the plastic flow stress of these aluminum alloys is really sensitive on the strain rates. The aluminum alloys have strain rate sensitivity due to a thermally-activated resistance effect of short-range barriers. The third kind of dynamic strain aging occurs at temperature of 200−600 K. Finally, based on the mechanism of dislocation motion, a physically based model is established. The theoretical predictions agree well with the experimental results, and it can be easily used in the engineering application.
Key words: aluminum alloy; plastic flow; strain rate; dynamic strain aging; constitutive model
