Ti-1100铸态合金的变形行为及本构模型研究  

Deformation Behavior and Constitutive Model of Ti-1100 As-Cast Alloy

作　　者：贾宝华 刘翔 顾永强 李革 Jia Baohua;Liu Xiang;Gu Yongqiang;Li Ge(School of Civil Engineering,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学土木工程学院,内蒙古包头014010

出　　处：《稀有金属》2020年第10期1019-1028,共10页Chinese Journal of Rare Metals

基　　金：内蒙古自治区自然科学基金面上项目(2016MS0112);内蒙古自治区高等学校科学研究项目(NJZY16156);内蒙古科技大学创新基金项目(2016QDL-B11)资助。

摘　　要：采用高温炉配合WDW-300型电子万能试验机对Ti-1100铸态合金进行等温压缩实验,得到了合金在温度25~800℃、应变速率1×10-4~1×10-2s-1条件下的真应力-真应变曲线,分析了合金的变形行为,基于实验数据建立了本构模型。结果表明:Ti-1100合金在800℃时,流变应力在同一温度下随着应变速率的增加而增加,在25~600℃时流变应力随应变速率增加的变化相对800℃较小,在应变速率不变的前提下,屈服应力随着温度的升高而降低。利用真应力-真应变曲线基于Arrhenius双曲正弦本构模型建立了包含应变项,温度在25~800℃大温度范围的力学本构模型,对模型的计算值和实验值进行了比较,同时采用实验值与计算值的平均相对误差绝对值(AARE)定量检验所建本构模型的精度,验证了模型的可靠性。通过扫描电镜(SEM)对合金的断面和内部显微组织进行观察,发现合金在常温条件下,压缩断面为以河流花样的脆性断裂为主并在局部出现韧窝形状,合金内部的片状组织在高温情况下发生了明显的弯曲、折叠、间距变小。The isothermal compression experiments of Ti-1100 as-cast alloy were conducted by WDW-300 electronic universal testing machine.A high-temperature furnace was used to provide an accurate temperature control and measurement during testing.The true stress-true strain curves of the alloy at temperatures ranging from 25 to 800 ℃ and strain rates ranging from 1×10-4 to 1×10-2 s-1 were obtained,the deformation behavior of the alloy was analyzed.And based on experimental data,the constitutive model for the alloy was established.The results showed that the flow stress of Ti-1100 as-cast alloy increased with the increase of strain rate at the same temperature of 800 ℃,but this phenomenon was not obvious at 25~600 ℃.When the strain rate was constant,the yield strength decreased with increasing temperature.Based on the Arrhenius hyperbolic sinusoidal constitutive model,a constitutive model with temperature range of 25~800℃ was established which included strain factors.The calculated data by the constitutive model with experimental values were compared using average absolute value of relative error(AARE)to verify precision accuracy of the model.And then the reliability of the model was verified.The section and internal microstructure of the alloy were observed by scanning electron microscope(SEM).At room temperature,it was found that the compression section of the alloy was mainly brittle fracture of river pattern and dimple shape appeared locally.The internal lamellar structure of the alloy was obviously bent,folded,and pitched at high temperature.

关 键 词：Ti-1100铸态合金 压缩变形 本构模型 应变速率 

分 类 号：TG146.23[一般工业技术—材料科学与工程]