初始组织特征对2E12铝合金热变形行为的影响

制备了富含大量共晶组织、过饱和固溶体以及富含粗大析出相3种典型组织特征的2E12合金。结合热模拟实验和显微组织观察,针对3种合金铸锭在变形温度为340~490℃、应变速率为0.001~10s-1下的变形行为开展研究。结果表明:组织特征对合金的热变形行为有显著影响。在3种合金中,富含粗大析出相合金的峰值应力较高而富含大量共晶组织合金的峰值应力较低。3种合金的流变应力均可用双曲正弦本构关系来描述。3种合金的变形激活能分别为178.6,222.1,154.9kJ/mol。利用加工图确定热变形的流变失稳区,富含粗大析出相合金具有较大的可加工范围而富含大量共晶组织合金的可加工范围最小。

Effects of Initial Microstructure Characteristics on Hot Deformation Behaviors of 2E12 Aluminum Alloy

Three alloys with different microstructure characteristics were prepared ,which microstructures were characterized as enriched with eutectics ,supersaturated solid solution and coarse precipitates .Combined isothermal hot compression test and microstructure observation ,the hot deformation behaviors of three alloys were studied in the temperature range of 340‐490℃ and strain rate range of 0 .001‐10s-1 .The results show initial microstructure characteristics have significant influences on the hot deformation of alloys .Among three alloys ,the alloy enriched with coarse precipitates has the largest peak stress value while the alloy enriched with eutectics has the smallest one .The flow behaviors of three alloys were described by the hyperbolic sine constitutive equations .The deformation activation energy for three alloys calculated to be 178 .6 ,222 .1 , 154 .9kJ/mol ,respectively .The processing maps were calculated and analyzed according to the dynamic mate‐rials model .Among three alloys ,the alloy enriched with coarse precipitates has the widest processing range while the alloy enriched with eutectics has the narrowest one .