一种新型亚稳β钛合金的热变形本构模型  

Constitutive Model for A New Kind of Metastable β Titanium Alloy during Hot Deformation

作　　者：强洪夫[1] 王哲君 王学仁[1] 王广[1] 

机构地区：[1]第二炮兵工程大学201室,陕西西安710025

出　　处：《稀有金属》2011年第6期823-828,共6页Chinese Journal of Rare Metals

基　　金：国家安全重大基础研究(973-61338)资助项目

摘　　要：基于新型亚稳β钛合金Ti2448在温度范围为1023～1123 K,应变速率范围为63.000～0.001 s-1的等温热压缩流动应力曲线特征,采用经典的应力-位错密度关系式和动态再结晶动力学模型构建了完整描述亚稳β钛合金热变形流动应力与应变、应变速率和变形温度关系的本构模型。位错密度变化方程和Avrami方程被用来分别描述合金在高(≥1 s-1)低(<1 s-1)应变速率下呈现的动态回复(DRV)和动态再结晶(DRX)两种不同的变形机制。最终通过应用全局优化求解非线性方程的新方法确定本构模型中的相关参数。根据本文所建模型得到的预测曲线和实验曲线吻合较好,能够有效预测Ti2448在热变形过程中的流动应力,为构建亚稳β钛合金热变形本构模型提供一种有效方法。Based on the characteristics of flow stress curves for a new kind of metastable β titanium alloy Ti2448 from isothermal hot compression tests,in a wide range of temperatures（1023~1123 K）,and strain rates（63~0.001 s-1）,the classical flow stress-dislocation density relation and kinetics of dynamic recrystallization were used to develop a model to describe the relation between flow stress and strain,strain rate and deformation temperature completely.The dislocation model and the Avrami equation were used to describe the different softening mechanism of the alloy at high and low strain rates,which were dynamic recovery（DRV） and dynamic recrystallization（DRX）,respectively.Additionally the material constants were determined by optimization strategies,which was a new method to solve the nonlinear equation.The stress-strain curves predicted by the developed model fitted with the experimental results,which proved that the developed model could predict the flow stress for Ti2448 titanium alloy validly and provide an effective way to model the deformation behavior of metastable β titanium alloy at hot deformation condition.

关 键 词：亚稳Β钛合金 热变形 本构模型 动态回复 动态再结晶 

分 类 号：TG146.2[一般工业技术—材料科学与工程]