摘要
The relationship among microstructure,mechanical properties and texture of TA32 titanium alloy sheets during hot tensile deformation at 800℃was investigated.In the test,the original sheet exhibited relatively low flow stress and sound plasticity,and increasing the heat treatment temperature resulted in an increased ultimate tensile strength(UTS)and a decreased elongation(EL).The deformation mechanism of TA32 alloy was dominated by high angle grain boundaries sliding and coordinated by dislocation motion.The coarsening of grains and the annihilation of dislocations in heat-treated specimens weakened the deformation ability of material,which led to the increase in flow stress.Based on the high-temperature creep equation,the quantitative relationship between microstructure and flow stress was established.The grain size exponent andαphase strength constant of TA32 alloy were calculated to be 1.57 and 549.58 MPa,respectively.The flow stress was accurately predicted by combining with the corresponding phase volume fraction and grain size.Besides,the deformation behavior of TA32 alloy was also dependent on the orientation of predominantαphase,and the main slip mode was the activation of prismaticslip system.The decrease of near prism-oriented texture in heat-treated specimens resulted in the enhancement of strength of the material.
研究TA32钛合金板材在800℃热拉伸变形过程中显微组织、力学性能和织构之间的关系。在实验中,原始板材表现出较低的流动应力和良好的塑性,随着热处理温度的升高,材料的抗拉强度增加,伸长率降低。TA32钛合金的变形机制是以大角晶界滑移为主,并通过位错运动协调变形。热处理试样中晶粒粗化和位错湮灭削弱材料的变形能力,从而导致流动应力的增加。基于高温蠕变方程,建立显微组织与流变应力的定量关系。TA32合金的晶粒影响因子和α相强度系数分别为1.57和549.58 MPa。通过综合相应的相体积分数和晶粒尺寸可以准确预测材料的流动应力。此外,TA32合金的变形行为还与α相晶粒的取向相关,其主要滑移方式为柱面滑移系的开动。热处理试样中近柱面织构的减少同样导致材料强度的提高。
基金
Project(51805256)supported by the National Natural Science Foundation of China。
