Ti40阻燃合金大晶粒超塑性变形特性及唯象型本构关系研究  

Research on superplastic deformation behavior and phenomenological constitutive relationship of Ti40 burn-resistant alloy with large grains

作　　者：张学敏[1,2] 李悦[1] 曾卫东[2] 焦奔奇 曹宇霞 袁战伟[1] ZHANG Xue-min;LI Yue;ZENG Wei-dong;JIAO Ben-qi;CAO Yu-xia;YUAN Zhan-wei(School of Materials Science ＆ Engineering, Chang＇an University, Xi＇an 710064, China;State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China)

机构地区：[1]长安大学材料科学与工程学院,陕西西安710064 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《塑性工程学报》2018年第2期189-195,共7页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51504037);中国博士后科学基金资助项目(2017M623085);西北工业大学凝固技术国家重点实验室开放课题(SKLSP201630)

摘　　要：对具有粗大晶粒的Ti40阻燃合金进行了超塑性拉伸试验，确定了其可实现大晶粒超塑性的变形参数区间，并建立了该合金大晶粒超塑性唯象型本构关系。结果表明：在低温高应变速率条件下（温度≤800℃，应变速率≥5×10^-3s^-1）Ti40阻燃合金不具备大晶粒超塑性，在高温低应变速率条件下具有良好的大晶粒超塑性能，最大伸长率436％出现在840℃，1×10^-3s^-1条件下；真应力一真应变曲线呈典型的4阶段特征；应变速率敏感指数m值随变形温度的升高先增大后保持不变，最大达到0．41；基于Arrhenius方程计算的Ti40合金超塑性变形的激活能为263．3kJ·mol^-1；基于BP神经网络构建本构模型，其误差分析表明平均相对误差仅为2．342％，预测的平均相对误差仅为2．715％，说明该本构模型具有较高的精度。The superplastic tensile tests of Ti40 burn-resistant alloy with large grains were conducted, the intervals of deformation parameters in which can achieve the large-grained superplasticity were determined, and the phenomenological constitutive equation of superplastic deformation of Ti40 alloy with large grains was established. The results indicate that the large grain Ti40 alloy does not exhibit superplasticity at the conditions of low temperatures and high strain rates （ T≤ 800 ℃ , ε≥ 5 × 10^-3s^-l ） , however, good superplasticity can be obtained at the conditions of high temperatures and low strain rates, and the maximum elongation of 436% occurs at the condition with temperature of 840℃ , strain rate of 1×10^-3s^-1. The true stress-strain curves present the clas- sic characteristic of four stages. The strain rate sensitivity exponent m increases first and then remains unchanged with increasing de- formation temperatures and the maximum of m is 0.41. The activation energy of Ti40 alloy superplastic deformation was calculated by Arrhenius equation and the value was 263.3 kJ · mol^-1. The phenomenological constitutive equation of Ti40 alloy was construc- ted by BP neural networks. Error analysis shows that the mean relative error value is 2. 342% and the mean relative error value for prediction is 2.715 % , indicating a good accuracy of the constitutive equation.

关 键 词：TI40阻燃钛合金 大晶粒 超塑性 本构关系 

分 类 号：TG359[金属学及工艺—金属压力加工]