【摘要】 TiAl合金具有优异的比强度、抗氧化、抗蠕变等特性，使其在高温结构材料领域有着广阔的应用前景。掌握其在近服役条件下的组织稳定性规律是实现其工程化应用的必然要求。片层结构是TiAl合金中最重要的微观结构形态，本文介绍了TiAl合金片层结构的连续粗化和不连续粗化类型，讨论了影响TiAl合金不连续粗化行为的各种因素，包括温度、时间、Al含量和片层组织的各向异性特性等。值得注意的是，目前的研究对不连续粗化转变与片层组织各向异性特性之间未能建立明确的关系，其过程中的物理冶金原理尚不明确，因此，需要从各向异性角度进一步丰富和完善对TiAl合金不连续粗化转变机理的认识，这对后续TiAl合金材料的实际应用设计具有重要的意义。最后，分析了TiAl合金不连续粗化行为的热力学驱动力来源，包括化学自由能和界面能，并简述了不连续粗化在温度、时间和Al含量影响下表现出的动力学特征。更多还原

【Abstract】 TiAl alloy has excellent specific strength,oxidation resistance and creep resistance,which make it have a broad application prospect in the field of high temperature structural materials,and it is necessary to master the law of its organization stability in the near service condition to realize its engineering application.Lamellar structure is the most important microstructure in TiAl alloy.In this summary,the types of continuous and discontinuous coarsening of TiAl alloy lamellar structure were introduced.Various factors affecting the discontinuous coarsening behavior of TiAl alloy,including temperatu re,time,Al content and anisotropy of lamellar structu re,were discussed.It is worth noting that no clear relationship has been established between the discontinuous coarsening transition and the anisotropy properties of the laminar structure,and the principle of physical metallurgy in the process is still unclear.Therefore,it is necessary to further enrich and improve the understanding of the discontinuous coarsening transition mechanism of TiAl alloy from the perspective of anisotropy.This is of great significance for the subsequent practical application design of TiAl alloy material.Finally,the thermodynamic driving forces of the discontinuous coarsening behavior of TiAl alloy,including chemical free energy and interfacial energy,were analyzed,and the kinetic characteristics of discontinuous coarsening under the influence of temperature,time and Al content were briefly described.更多还原