(1. 南京航空航天大學(xué) 機(jī)電學(xué)院，南京 210016；
2. 常州機(jī)電職業(yè)技術(shù)學(xué)院 模具技術(shù)系，常州 213164)
摘 要: 為了研究同步冷卻熱成形工藝對可熱處理鋁合金的顯微組織演變規(guī)律以及強(qiáng)化機(jī)制的影響，選用H18態(tài)AA2024鋁合金板料進(jìn)行同步冷卻熱成形及自然時效試驗，并進(jìn)行力學(xué)性能測試、光學(xué)顯微組織觀察及TEM分析。結(jié)果表明：同步冷卻熱成形工藝對AA2024鋁合金的顯微組織影響明顯；H18態(tài)AA2024鋁合金板料經(jīng)過同步冷卻熱成形及96 h自然時效后，試樣變形區(qū)的位錯密度增加，并出現(xiàn)細(xì)針狀的Al2CuMg(S′)相，使得變形區(qū)的屈服強(qiáng)度及抗拉強(qiáng)度分別較冷沖壓工藝試樣提高4%、12%；此時，AA2024鋁合金的強(qiáng)化機(jī)制主要是彌散相Al20Cu2Mn3(T相)和沉淀相Al2CuMg(S′相)對位錯的釘扎作用，以及位錯間的相互作用。
關(guān)鍵字: 同步冷卻熱成形；AA2024鋁合金；顯微組織；強(qiáng)化機(jī)制；力學(xué)性能
（1. College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2. Department of Mould Technology, Changzhou Institute of Mechatronic Technology, Changzhou 213164, China）
Abstract:Hot forming test with synchronous cooling, metallographic and TEM observation and tensile test were performed to investigate the influence of hot forming with synchronous cooling operations on the microstructure evolution and strengthening mechanism of AA2024-H18 aluminum alloy. The results show that, the yield strength of hot formed AA2024 sheet with 96 h natural aging is 4%, which is superior to that of traditionally formed sheet, and meanwhile, the tensile strength is increased by 12%. Based on the microstructure observation and analysis, the strengthening is generated by the increase of the dislocation density and precipitation of some fine acicular particles in form of Al2CuMg (S′). The main strengthening mechanism of AA2024 aluminum alloy underwent hot forming with synchronous cooling is the pinning effect of dispersoid phase Al20Cu2Mn3 (T) and precipitated phase Al2CuMg (S′) on dislocation as well as the interaction of dislocation.
Key words: hot forming with synchronous cooling; AA2024 aluminum alloy; microstructure; strengthening mechanism; mechanical behavior
