CAJ | 학술논문

通过等温压缩试验,对γ-TiAl基合金(Ti-47％Al合金,摩尔分数)在温度为900～1 200℃和应变速率为0.001～0.02 s-1条件下的变形行为进行研究.研究发现,变形温度、应变速率和应变对该合金的流动应力有很大影响,变形温度越高,应变速率越小,流动应力就越小.利用双曲正弦方程求得该合金的应力指数n为2.6和激活能Q为321.2 kJ/mol.运用逐步回归的方法,建立该合金的流动应力模型,并用实验数据对该模型进行评估和验证.表明提出的模型能很好地用来预测该合金在热变形过程中的流动应力和力学性能.
통과등온압축시험,대γ-TiAl기합금(Ti-47％Al합금,마이분수)재온도위900～1 200℃화응변속솔위0.001～0.02 s-1조건하적변형행위진행연구.연구발현,변형온도、응변속솔화응변대해합금적류동응력유흔대영향,변형온도월고,응변속솔월소,류동응력취월소.이용쌍곡정현방정구득해합금적응력지수n위2.6화격활능Q위321.2 kJ/mol.운용축보회귀적방법,건립해합금적류동응력모형,병용실험수거대해모형진행평고화험증.표명제출적모형능흔호지용래예측해합금재열변형과정중적류동응력화역학성능.
The hot deformation behavior of a γ-TiAl based alloy (Ti-47％Al,mole fraction) was investigated by isothermal compression tests performed at elevated temperature of 900-1 200 ℃ and strain rate of 0.001-0.02 s-1.The effect of temperature,strain rate and strain on the flow stress of the alloy was evaluated.The higher the deformation temperature and the lower the strain rate,the smaller the deformation resistance.The stress exponent,n,and the apparent activation energy,Q,were determined as 2.6 and 321.2 kJ/mol by the sine hyperbolic law,respectively.Based on the experimental results by the orthogonal method,a flow stress model for hot deformation was established by stepwise regression analysis.Then the effectiveness of the flow stress model was confirmed by other experimental data different from those experimental data used to establish the model.And it was proved that the flow stress model can well predict the mechanical behavior and flow stress of the alloy during hot deformation.