(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 湖南人文科技學(xué)院 機(jī)電工程系，婁底 417000；
3. 中南大學(xué) 輕合金研究院，長(zhǎng)沙 410083)
摘 要: 通過拉伸實(shí)驗(yàn)、慢應(yīng)變速率實(shí)驗(yàn)、剝落腐蝕實(shí)驗(yàn)、掃描電鏡和透射電鏡觀察，研究新型熱機(jī)械處理對(duì)Al-Zn-Mg-Cu合金顯微組織及性能的影響。結(jié)果表明：冷變形最終熱機(jī)械處理能夠使合金在塑性不顯著降低的情況下，提高合金的強(qiáng)度，溫變形最終熱機(jī)械處理能有效彌補(bǔ)常規(guī)最終熱機(jī)械處理后伸長(zhǎng)率較低的缺陷，同時(shí)能有效改善合金的抗剝落腐蝕性能；回歸后冷變形可提高合金強(qiáng)度，但降低了合金的伸長(zhǎng)率；回歸后溫變形處理能使合金獲得良好的綜合性能，如力學(xué)性能、抗應(yīng)力腐蝕性和抗剝蝕性能。新型熱機(jī)械處理改善合金性能的機(jī)理是合金晶粒形態(tài)、位錯(cuò)、初生相以及析出相等顯微組織結(jié)構(gòu)的協(xié)同作用。
關(guān)鍵字: 高強(qiáng)鋁合金；時(shí)效；熱機(jī)械處理；應(yīng)力腐蝕
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Department of Mechanical and Electrical Engineering,
Hunan University of Humanities Science and Technology, Loudi 417000, China;
3. Light Alloy Research Institute, Central South University, Changsha 410083, China）
Abstract:The effects of new thermomechanical treatment (TMT) on the microstructure and properties of Al-Zn-Mg-Cu alloy were studied by tensile test, slow strain rate tensile test (SSRT)，exfoliation corrosion test (EXCO), scanning electron microscopy and transmission electron microscopy. The results indicate that the cold deformation final thermomechanical treatment (FTMTc) process can significantly increase the strength of the alloy without obvious plasticty loss，and warm deformation find thermomechanical treatment (FTMTw) at 200 ℃ can simultaneously improve the elongation and EXCO resistance. Cold rolling after regression (RRCA) can obtain high strength but low elongation, while warm rolling after regression (RRWA) can obtain good mechanical properties and a good combination of stress corrosion resistance (SCR) and exfoliation corrosion resistance. The mechanism of the new TMT process that improves the properties of the alloy is the synergistic effect of composite structures, such as grain structure, dislocations, as well as the size and distribution of primary phase and precipitate phase.
Key words: high strength aluminum alloy; ageing; thermomechanical treatment; stress corrosion
