自生Al2O3颗粒强化TiAl基合金组织微细化机理研究

陶瓷增强的TiAl基复合材料由于含有第二相颗粒及形成高密度位错的界面结构，有望有效地促进热变形过程中动态再结晶行为，因此，陶瓷增强相增强TiAl基复合材料具备通过热塑性变形制备细晶材料的潜力。然而，目前关于陶瓷增强相增强TiAl合金的热变形行为很少，机理尚不清楚。本项目拟以Al2O3颗粒强化TiAl 基合金为研究对象，研究纳米Al2O3颗粒和TiAl基体之间的晶体学取向关系，及其界面结构和化学本质；在此基础上，采用基于动态材料模型的加工图技术和变形本构关系模型实现该合金变形行为的精确表征；通过形变动力学分析结合微观组织的演化和相变规律，剖析Al2O3颗粒强化TiAl合金的热变形机制，揭示细晶自生Al2O3颗粒强化TiAl基合金的形成规律与条件。本项目的开展不仅对丰富再结晶理论具有重要的学术价值和理论意义，而且有望为开发细晶TiAl合金提供新的技术原型。

Ceramic particles reinforced TiAl matrix composites have small second phase particles, interface microstructure containing high density dislocations. These microstructures may greatly enhance the dynamic recrystallization behavior during hot deformation and make the TiAl matrix be potentially fine-grained material. In this project, Al2O3 reinforced TiAl matrix composites system is going to be selected as the object of study. The orientation relationships that coexist between the oxides and the TiAl matrix, and the structure and chemistry of metal/oxide interfaces will be investigated. The hot deformation behaviors of Al2O3 reinforced TiAl matrix alloys are going to be studied to clarify the deformation mechanism. Effect of Al2O3 on dynamic recrystallization of γ phase and β phase will be explored, and the effect of deformation parameters on grain refinement will be discussed. The research results would not only provide the important academic value and theoretical significance in enriching the theory of dynamic recrystallization, but also have the practical meaning to provide a new prototype of developping fine-grained TiAl alloys.