(西北工業(yè)大學(xué) 航空學(xué)院，西安 710072)
摘 要: 建立了塑性流動本構(gòu)模型，對Al3003-H12、2219-T87、7050-T7451、2024-T351和LY12-cz 5種典型的鋁合金在應(yīng)變率從10−4 /s到8 000 /s，初始溫度從77 K到800 K以及真實(shí)應(yīng)變超過0.50條件下進(jìn)行系統(tǒng)實(shí)驗(yàn)，并對塑性流動行為進(jìn)行分析。結(jié)果表明：這些鋁合金材料具有應(yīng)變率效應(yīng)；鋁合金材料應(yīng)變率敏感性可歸于短程障礙對熱激活位錯(cuò)運(yùn)動的影響；在200~600 K時(shí)，這些材料存在第三類動態(tài)應(yīng)變時(shí)效現(xiàn)象。基于熱激活位錯(cuò)運(yùn)動機(jī)制，推出一個(gè)物理概念的本構(gòu)模型，比較得出的模型預(yù)測結(jié)果和實(shí)驗(yàn)結(jié)果一致，可方便用于工程應(yīng)用。
關(guān)鍵字: 鋁合金；塑性流動；應(yīng)變率；動態(tài)應(yīng)變時(shí)效；本構(gòu)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
