钛-TiAl复合板“热-电”耦合轧制变形行为及界面结合机制研究

Titanium-TiAl composite sheets own promising prospect in aviation and aerospace fields, on account of the combination of high specific strength and service temperature of TiAl intermetallic, and the outstanding elongation and toughness of titanium alloy. While the huge deformation resistance, poor deformation coordination, and the thick interface compounds limit their development and further application. In order to improve the deformability and decrease the deformation resistance, electropulsing and hot roller technology are adopted to develop a new rolling bonding technology of the Titanium-TiAl composite sheets coupling with the effect of thermal and electropulsing. The hot deformation suitability of titanium and TiAl alloy are explored, and the finite element model coupled with thermal, electropulsing and stress is established. The thermoplastic rheological behavior and coordinated deformation mechanism of titanium and TiAl alloy during rolling bonding process are illustrated. The effect of electropulsing and rolling parameters on the dynamic recrystallization, dislocation motion, interface atom diffusion，interface compounds, macro and micro mechanical properties are studied. The evolution of microstructure and mechanical properties of rolling process of titanium-TiAl composite sheets are illustrated in the end. The research of this project will not only promote the rolling of titanium-TiAl composite sheets, but also improve the electroplastic manufacture theoretical system.

钛-TiAl复合板兼具TiAl金属间化合物比强度高、服役温度高的优点和钛合金塑性高、韧性好的特点，在航空航天领域极具应用前景。然而钛-TiAl复合板轧制变形抗力大、双金属变形协调性差、界面硬脆化合物层厚，制约了其开发和应用。本项目提出将脉冲电流和热辊技术应用于钛-TiAl复合板轧制过程，降低变形抗力，提高变形能力，创新一种钛-TiAl“热-电”耦合无包套轧制复合新工艺，探索钛、TiAl组元材料热变形适配性窗口，构建钛-TiAl复合板轧制成形“热-电-力”耦合有限元模型，阐明复合能场下双金属热塑性流变行为，揭示双金属“热-电”耦合轧制协调变形机理，明晰“热-电”耦合轧制工艺对再结晶、位错、界面原子扩散、化合物和宏、微观力学性能的影响规律，揭示“热-电”耦合轧制界面结合机制及强韧化机理，构建工艺-组织-性能关系规律，对促进钛-TiAl复合板的开发，拓展和完善电致塑性加工理论具有重要的科学意义。

本项目针对钛-TiAl复合板轧制包套热轧存在的变形不协调、温降严重等问题，提出将特种能场辅助技术应用于钛-TiAl复合板轧制过程，通过在塑性变形过程中施加脉冲电流降低变形抗力，提高变形能力，同时依靠电磁感应加热轧辊，开发了一种钛-TiAl多能场辅助轧制复合工艺，开展了钛合金电流辅助塑性变形行为研究，分析了脉冲电流热及非热效应对其塑性变形能力和显微组织演变行为的影响规律，构建了电流辅助塑性变形的本构方程；开展了TiAl合金热塑性变形模拟，计算了其热变形激活能，构建了热场作用下的本构方程，建立了热加工窗口，分析了其动态软化机制；开展了TiAl合金以及钛-TiAl复合板近等温轧制有限元模拟，分析了不同轧辊温度和轧制工艺参数对其应力、应变以及缺陷的影响规律，明确了最优轧制工艺参数；基于有限元模拟结果，设计轧辊电磁感应加热装置，优化电磁感应加热工艺，搭建了轧辊电磁感应加热测试平台和近等温轧制试验装置，验证了电磁感应加热轧辊的有效性；开展了钛-TiAl复合板多场辅助轧制试验研究，分析了组坯方式、轧制温度、压下率等工艺参数对复合板显微组织和力学性能的影响规律，阐明了轧制界面结合机制及强韧化机理，构建工艺-组织-性能关系规律，试制了钛-TiAl复合板。研究成果在本领域著名期刊发表期刊论文22篇，其中SCI论文12篇，EI论文3篇，申请国家发明专利7项，授权3项。获山西省科技进步一等奖1项，山西省“五小”创新大赛二等奖1项。