(1. 江苏大学 材料科学与工程学院，镇江 212013；
2. 江苏豪然喷射成形合金有限公司，镇江 212009)
摘 要: 利用Gleeble-3500型热力模拟试验机对挤压态喷射成形Al-Zn-Mg-Cu系高强铝合金进行高应变速率下的热压缩试验，系统研究了材料在变形温度350~450 ℃，高应变速率1~20 s-1条件下的高温塑性变形行为。考虑绝热温升因素影响，采用外推法修正材料的流变应力曲线，以此构建材料本构模型；基于动态材料模型(dynamic materials model,DMM)构建材料的热加工图，并确定不同变形条件区域内的微观组织特征。结果表明：该合金流变应力曲线呈现典型的动态回复特征；随着应变速率的升高绝热温升现象愈发明显；材料热加工图和不同变形区域组织特征表明，该合金存在3个危险加工区间分别为350~420 ℃、1~3 s-1，350~390 ℃、7~20 s-1和425~450 ℃、2~20 s-1，应避免在危险区间加工，防止出现失稳和开裂现象。存在2个安全加工区间350~370 ℃、4~7 s-1和395~425 ℃、14~20 s-1，应优先选择在该热加工窗口区域进行热加工。
关键字: 喷射成形；Al-Zn-Mg-Cu合金；高应变速率；热变形
（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
