(1. 江蘇大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212013；
2. 江蘇豪然噴射成形合金有限公司，鎮(zhèn)江 212009)
摘 要: 利用Gleeble-3500型熱力模擬試驗機對擠壓態(tài)噴射成形Al-Zn-Mg-Cu系高強鋁合金進行高應(yīng)變速率下的熱壓縮試驗，系統(tǒng)研究了材料在變形溫度350~450 ℃，高應(yīng)變速率1~20 s-1條件下的高溫塑性變形行為。考慮絕熱溫升因素影響，采用外推法修正材料的流變應(yīng)力曲線，以此構(gòu)建材料本構(gòu)模型；基于動態(tài)材料模型(dynamic materials model,DMM)構(gòu)建材料的熱加工圖，并確定不同變形條件區(qū)域內(nèi)的微觀組織特征。結(jié)果表明：該合金流變應(yīng)力曲線呈現(xiàn)典型的動態(tài)回復(fù)特征；隨著應(yīng)變速率的升高絕熱溫升現(xiàn)象愈發(fā)明顯；材料熱加工圖和不同變形區(qū)域組織特征表明，該合金存在3個危險加工區(qū)間分別為350~420 ℃、1~3 s-1，350~390 ℃、7~20 s-1和425~450 ℃、2~20 s-1，應(yīng)避免在危險區(qū)間加工，防止出現(xiàn)失穩(wěn)和開裂現(xiàn)象。存在2個安全加工區(qū)間350~370 ℃、4~7 s-1和395~425 ℃、14~20 s-1，應(yīng)優(yōu)先選擇在該熱加工窗口區(qū)域進行熱加工。
關(guān)鍵字: 噴射成形；Al-Zn-Mg-Cu合金；高應(yīng)變速率；熱變形
（1. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. Jiangsu Haoran Spray Forming Alloy Co., Ltd., Zhenjiang 212009, China）
Abstract:The thermal compression test of extruded spray formed Al-Zn-Mg-Cu high strength aluminum alloy at high strain rate was performed on Gleeble-3500 thermo-mechanical simulator. The high temperature plastic deformation behavior of the material at deformation temperature of 350-450 ℃ and high strain rate of 1-20 s-1 was systematically studied. Considering the influence of adiabatic heating, the flow stress curve of material was corrected by extrapolation, and the material constitutive model was constructed. The processing maps were constructed based on the dynamic material model, and the microstructure characteristics in different deformation conditions were determined. The results show that the flow stress curves of the alloy exhibit typical dynamic recovery characteristics. With the increase of strain rate, the adiabatic temperature rise becomes more obvious. The processing maps and the microstructure characteristics of different deformation regions show that there are three hazardous processing zones at (350-420 ℃, 1-3 s-1), (350-390 ℃, 7-20 s-1) and (425-450 ℃, 2-20 s-1) which should be avoided to prevent the occurrence of instability and cracking in the hazardous area. There are two safe processing zones, (350-370 ℃, 4-7 s-1) and (395-425 ℃, 14-20 s-1) which should be selected for hot working.
Key words: spray forming; Al-Zn-Mg-Cu alloy; high strain rate; hot deformation
