基于β/B2相自润滑的TiAl-RE合金优化设计与管材制备基础研究

B2-containing TiAl-RE alloy ( the γ-based TiAl alloy with B2 phase, which contains a certain amount of rare earth elements), can be widely served as TiAl tubular products and high-temperature structural components due to its excellent properties, including good workability and performances, which contributed by the self-lubricating effect of β/B2 phase. The deformability of TiAl-RE alloy is closely related to its composition, preparation and microstructure. In this work, a B2-containing TiAl-RE alloy, Ti-45Al-3Fe-2Mo alloy with our own copyright, will be studied systematically for modified its microstructure and properties by some rare earth elements (RE). We will focus on: the existence and interface of RE; effect of RE on the microstructure and properties of TiAl alloy; acceleration of RE and the self-lubricating effect of β/B2 phase on its deformation; the deformation mechanism related with the multi-field cooperation and strain rate, stain, stress, temperature and phases, et al.; the changing trend and influential factors of RE and B2 phase during hot extrusion; the modified processing for forming and control of TiAl tubular products. According to the results above, the influence of RE on the microstructure and properties of B2-containing TiAl-RE alloy can be set up. The multi-field-cooperation deformation mechanism based on β/B2-phase self-lubricating effect can be obtained. And the prototype for manufacturing tubular products made by B2-containing TiAl-RE alloy via hot extrusion can be formed.

含B2相的TiAl-RE合金，由于其β/B2相的自润滑作用，在热挤压成型方面有突出优势，可广泛用于TiAl管材和高温结构件。TiAl-RE合金的成型能力与其成分、组织和结构密切相关。本项目在自主开发的含B2相Ti-45Al-3Fe-2Mo合金基础上，针对稀土元素RE改性在改良含B2相TiAl合金组织和性能方面的应用，重点研究RE在合金中的存在形式和界面关系、对合金组织和结构的优化及性能影响的规律；RE及β/B2相自润滑对变形的促进作用；含B2相的TiAl-RE合金的形变多场协作变形机制；RE及B2相在低温热挤压管材中的演变规律与作用；确定TiAl合金管材成型控制与组织优化机理。通过上述研究，建立稀土元素对含B2相γ-TiAl基合金的组织和性能影响的规律；获得基于β/B2相自润滑的TiAl-RE合金热变形行为多场协作控制理论；形成低成本含 B2相的TiAl-RE合金低温热挤压成管的技术原型。

含B2相的TiAl-RE合金，由于其B2相的自润滑作用，在热挤压成型与控制方面有突出优势，可广泛用于TiAl管材和高温结构件。TiAl-RE合金的成型能力与其成分、组织和结构密切相关。本项目在自主开发的含B2相Ti-45Al-3Fe-2Mo合金基础上，针对稀土元素（RE）改性在改良含B2相TiAl合金组织和性能方面的应用，重点研究RE在合金中的存在形式和界面关系、对合金组织和结构的优化及性能影响的规律；RE及B2相自润滑对变形的促进作用；含B2相的TiAl-RE合金的形变多场协作变形机制；RE及B2相在低温热挤压管材中的演变规律与作用；确定TiAl合金管材成型控制与组织优化机理。通过上述研究，建立稀土元素对含B2相γ-TiAl基合金的组织和性能影响的规律；获得基于B2相自润滑的TiAl-RE合金热变形行为多场协作控制理论；最终形成了低成本含 B2相的TiAl-RE合金低温热挤压成管的技术。