Su Gang, Yun Zhong, Lin Yong-Cheng, He Dao-Guang, Zhang Song, Chen Zi-Jian
Light Alloy Research Institute, Central South University, Changsha 410083, China.
School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China.
Materials (Basel). 2021 Nov 9;14(22):6750. doi: 10.3390/ma14226750.
The flow behavior and microstructure change of the Ti-55511 alloy are investigated by thermal compression experiments with stepped strain rates. The phase transformation features, the dynamic recrystallization (DRX) behavior of the β matrix, the dynamic spheroidization mechanism of the lamellar α phase and the evolution of the β sub-grain size are quantitatively analyzed. A unified constitutive model is constructed to characterize the hot deformation features of the Ti-55511 alloy. In the established model, the work hardening effect is taken into account by involving the coupled effects of the equiaxed and lamellar α phases, as well as β substructures. The dynamic softening mechanisms including the dynamic recovery (DRV), DRX and dynamic spheroidization mechanisms are also considered. The material parameters are optimized by the multi-objective algorithm in the MATLAB toolbox. The consistency between the predicted and experimental data indicates that the developed unified model can accurately describe the flow features and microstructure evolution of the hot compressed Ti-55511 at stepped strain rates.
通过具有阶梯应变率的热压缩实验研究了Ti-55511合金的流变行为和微观结构变化。定量分析了相变特征、β基体的动态再结晶（DRX）行为、片状α相的动态球化机制以及β亚晶粒尺寸的演变。构建了一个统一的本构模型来表征Ti-55511合金的热变形特征。在建立的模型中，通过考虑等轴α相和片状α相以及β亚结构的耦合效应来考虑加工硬化效应。还考虑了包括动态回复（DRV）、DRX和动态球化机制在内的动态软化机制。通过MATLAB工具箱中的多目标算法对材料参数进行了优化。预测数据与实验数据之间的一致性表明，所建立起来的统一模型能够准确描述热压缩Ti-55511在阶梯应变率下的流变特征和微观结构演变。
