铸态Udimet720Li合金热变形行为及热加工图研究  

Hot Deformation Behavior and Hot Processing Map of As-Cast Udimet720Li Alloy

作　　者：汪兵兵 马平东 周建平[2] 姜宏[2] 陈小康 WANG Bingbing;MA Pingdong;ZHOU Jianping;JIANG Hong;CHEN Xiaokang(School of Aeronautical,Changji University,Changji Xinjiang 831100,China;School of Intelligent Manufacturing and Modern Industry,Xinjiang University,Urumqi Xinjiang 830017,China;TBEA Power Service Branch Company,Changji Xinjiang 831100,China)

机构地区：[1]昌吉学院航空学院,新疆昌吉831100 [2]新疆大学智能制造现代产业学院,新疆乌鲁木齐830017 [3]特变电工股份有限公司能源动力分公司,新疆昌吉831100

出　　处：《新疆大学学报（自然科学版中英文）》2024年第3期375-384,共10页Journal of Xinjiang University(Natural Science Edition in Chinese and English)

基　　金：新疆维吾尔自治区自然科学基金青年科学基金(联合基金)“航空难切削材料的短电弧-机械复合加工关键技术研究”(2022D01C738);昌吉学院校级科研项目“航空7075铝合金短电弧铣削加工工艺研究”(2022KY006)。

摘　　要：在变形温度为1 040~1 160℃、真应变速率为0.01~10 s^(-1)和变形量为60%条件下,对铸态Udimet720Li合金开展了热压缩实验.基于真应力-真应变数据,运用Arrhenius方程、动态材料模型理论和流变失稳判据理论建立了本构方程模型和热加工图,分析了合金热变形行为并结合微观组织验证了所建热加工图的准确性.结果表明:流变真应力对温度和真应变速率具有较强的敏感性,随着变形温度的升高和变形速率的减小流变真应力不断降低,温度越高,流变真应力达到稳态时对应的真应力和真应变越小,所建本构方程模型对合金流变真应力预测具有较高的准确性.当变形量为60%时,变形温度1 040~1 070℃和真应变速率5~10 s^(-1)范围内为合金变形失稳区,变形温度1 140~1 160℃、真应变速率0.01~0.20 s^(-1)范围内合金具有最优热加工性,该区功率耗散系数为0.32~0.40,合金可以获得晶粒细小的等轴匀晶组织.Hot compression tests of as-cast Udimet720Li superalloy were carried out at deformation temperature of 1040∼1160℃,strain rate of 0.01∼10 s^(-1) and height reduction of 60%.Based on the stress-strain data,the constitutive equation model and hot processing map were established by using Arrhenius equation,dynamic material model theory andflow instability criterion theory.The hot deformation behavior of the alloy was analyzed and the accuracy of the hot processing map was verified by the microstructure.The results show that theflow stress has a strong sensitivity to temperature and strain rate.With the increase of deformation temperature and the decrease of deformation rate,theflow stress decreases continuously.The higher the temperature,the smaller the corresponding stress and strain when theflow stress reaches the steady state.The constitutive equation has a high accuracy in predicting theflow stress of the alloy.When the height reduction is 60%,the alloy is in the deformation instability zone in the range of deformation temperature 1040∼1070℃and strain rate 5∼10 s^(-1),and the alloy has the best hot workability in the range of 1140∼1160℃and 0.01∼0.20 s^(-1).The power dissipation coefficient in this area is 0.32∼0.40,and the alloy can obtain equiaxed uniform crystal structure withfine grains.

关 键 词：铸态Udimet720Li合金 热变形 本构方程 热加工图 微观组织 

分 类 号：TG132.3[一般工业技术—材料科学与工程]