基于模糊理论的Ti-22Al-25Nb合金高温本构关系模型

运用Gleeble1500热模拟实验机对Ti-22Al-25Nb钛合金试样进行热模拟压缩试验,针对该合金高温变形过程时复杂的流变行为,以实验所得数据(变形温度940～1030℃,应变速率0.001～10s-1)为基础,从模糊集理论的本质特征出发,提出了一种基于模糊动态线性原理的本构模型,并与实验结果进行了对比。结果表明:基于模糊集理论建立的Ti-22Al-25Nb合金的高温本构关系模型是切实可行的,拟合程度较高,弥补了传统回归模型不能反映变形全过程的局限性,是一种有广泛应用前景的表征工程材料本构关系的便捷有效的方法。

Modeling the High-Temperature Constitutive Relationship of Ti-22Al-25Nb Alloy Based on Fuzzy Theory

The hot deformation characteristics of Ti-22Al-25Nb alloy were studied in the temperature range of 940-1030 oC and strain rate range of 0.001-10 s-1 using Gleeble 1500 thermal simulator. Based on the results obtained from the experiment for the complex flow deformation behavior, a constitutive model of Ti-22Al-25Nb alloy was established with the help of the fuzzy set theory. Simultaneously, a kind of fuzzy dynamic linear model was put forward to extract the feature of sample data for the complicated nonlinear relationship of thermodynamic parameters. Compared with the experimental value, the results of this study indicate that the method is feasible to construct a constitutive relationship model for this alloy and high in the degree of fitting. It can be used to make up for the limitations that traditional regression can not reflect the whole deformation process. It is not only a wide prospect of application but also a convenient way to characterize the constitutive model for Ti-22Al-25Nb alloy.