增材制造钛铝合金研究进展

Research progress of additive manufacturing of TiAl alloys

钛铝合金具有轻质、高强、耐高温等优异特性,在航空领域,特别是在航空发动机涡轮叶片上具有重要应用价值。然而,钛铝合金的室温脆性大、热变形能力低,使得采用传统的锻造、精密铸造、粉末冶金等技术均难以制造具有复杂形状,特别是具有内部空腔结构的钛铝合金叶片,限制了其性能的进一步提升。增材制造技术能够突破形状的制约,有望发展成为制造钛铝合金复杂结构零部件的新技术。目前,应用于钛铝合金的增材制造技术主要有电子束选区熔化、选区激光熔化和激光金属沉积。本文调研了增材制造钛铝合金领域2010~2020年的文献,对上述3类增材制造技术的原理和特性、所使用合金粉末的特性、打印构件的相组成、组织形貌和热处理工艺、宏观和微观力学性能及其在航空领域的应用等研究进行了对比分析和评述,并对增材制造钛铝合金发展中所存在的问题及下一步研发重点进行了总结和探讨。

TiAl alloys are promising structural metallic materials used in the field of aerospace especially in aero-engine turbine blade due to their relatively low density,high elastic modulus,excellent high temperature strength,good creep and oxidation resistance,etc.However,because of its brittleness at room temperature and poor hot deformability,it is difficult to manufacture the TiAl alloy blade with complex shape and internal cavity structure by traditional technologies of forging,precision casting and powder metallurgy,which hinders the further improvement of its performance.Additive manufacturing can break through the restriction of shape,and is expected to be a new technology for manufacturing of TiAl alloy parts with complex structure.At present,the additive manufacturing technologies used for TiAl alloys mainly include electron beam melting,selective laser melting,and laser metal deposition.In this paper,we investigate the literature of additive manufacturing of TiAl alloys in recent ten years.The three kinds of additive manufacturing technologies are analyzed and reviewed in terms of their principles and characteristics,the characteristics of the alloy powder used,the phase structure,microstructure,heat treatment process,macro-and micro-mechanical properties of printing TiAl alloys,and their applications in the aviation field.Existing problems and future development of additive manufacturing of the alloy are also discussed.