快速冷却细化TiAl合金组织研究进展

Research Progress on Microstructure Refinement of TiAl alloys by Rapid Cooling

TiAl合金具有低密度、高比强度、优异的抗氧化性能以及抗蠕变性能,但较低的室温塑性限制了其应用。细小的片层组织有助于改善TiAl合金的力学性能。快速冷却法细化TiAl合金组织具有工艺简单且操作方便等特点而备受关注。主要介绍了从3个相区:液相区、β相区和α相区进行快速冷却,并结合后续热处理实现组织细化,分析了不同温度区间和冷速对淬火组织的影响。主要从相变过程、细化原理、组织控制以及组织对性能的影响等方面展开,阐述了快速冷却法细化TiAl合金的研究进展,并对其存在的问题以及发展前景进行了讨论。

TiAl alloys have attractive properties such as low density,high modulus,excellent oxidation resistance and creep resistance at elevated temperatures,but the low room-temperature ductility limits their application.The fine lamellar microstructure contributes to the mechanical properties improvement of TiAl alloys.The method of refining the microstructure of TiAl alloys through rapid cooling has attracted much attention due to the simple process and easy operation.Rapid cooling from 3 regions,i.e.liquid phase,βphase andαphase with subsequent heat treatment for microstructure refinement,and the effects of different temperature and cooling rate on quenched microstructure are reviewed.From aspects of phase transformation,refinement mechanism,microstructure control and the effect of microstructure refinement on mechanical properties,the research status of the TiAl alloys microstructure refinement by rapid cooling are discussed.The disadvantages and the prospect of this refining method are also discussed.