Ge Gengwu, Zhang Laiqi, Xin Jingjing, Lin Junpin, Aindow Mark, Zhang Lichun
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China.
Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT, 06269-3136, USA.
Sci Rep. 2018 Apr 3;8(1):5453. doi: 10.1038/s41598-018-23617-7.
A constitutive equation based on the hyperbolic sinusoidal Arrhenius-type model has been developed to describe the hot deformation behavior of a β-γ Ti-Al alloy containing 8 at.% of Nb. Experimental true stress-true strain data were acquired from isothermal hot compression tests conducted across a wide range of temperatures (1273 K1473 K) and strain rates (0.001 s1 s), and the changes in the experimental conditions were reflected in the values of the Zener-Hollomon parameter. The impact of true strain was expressed through material constants (A, α, n and Q), and it was found that a 7th order polynomial is appropriate to express the relations between the true strain and these material constants. The average absolute relative error (AARE) and correlation coefficient (R) were used to evaluate the accuracy of the constitutive equation, and the values obtained were 6.009% and 0.9961, respectively. These results indicate that the type of constitutive equation developed here can predict the flow stress for this alloy with good accuracy over a wide range of experimental conditions. Thus, equations of this form could be applied more widely to analyses of hot deformation mechanism and microstructure evolution.
基于双曲正弦阿累尼乌斯型模型开发了一个本构方程，用于描述含8原子%铌的β-γ Ti-Al合金的热变形行为。通过在广泛的温度范围（1273K至1473K）和应变速率（0.001s至1s）下进行的等温热压缩试验获取了实验真应力-真应变数据，实验条件的变化反映在齐纳-霍洛蒙参数的值中。真应变的影响通过材料常数（A、α、n和Q）来表示，并且发现用七阶多项式来表示真应变与这些材料常数之间的关系是合适的。使用平均绝对相对误差（AARE）和相关系数（R）来评估本构方程的准确性，得到的值分别为6.009%和0.9961。这些结果表明，此处开发的本构方程类型能够在广泛的实验条件下较为准确地预测该合金的流动应力。因此，这种形式的方程可以更广泛地应用于热变形机制和微观结构演变的分析。
