摘要
TiAl基合金以其低密度、高比强度、耐烧蚀、良好的高温力学性能等优点成为新型轻质高温结构候选材料,自20世纪70年代以来备受关注。随着各种强韧化措施的研究不断深入,TiAl基合金的室温脆性问题逐步得到了解决。TiAl基合金成功应用于航空发动机叶片、航天飞行器蒙皮、舵翼、汽车排气阀等。然而,TiAl基合金高温抗氧化性能不足,限制了其作为高温零部件的应用。目前,主要通过整体合金化以及表面改性两种方式来改善TiAl基合金的高温抗氧化性能。整体合金化是在合金中添加Nb、Si、Mo、W、稀土等合金元素,促使合金表面形成致密的氧化层并提高氧化层与基体的结合力;表面改性主要包括表面合金化和表面涂层两种途径,表面合金化技术一般采用热扩散、离子注入、预氧化、激光表面合金化等方法,表面涂层技术是利用不同种类的涂层改善基体的表面性能,例如Ti-Al-X体系涂层、MCrAlY热障涂层、陶瓷涂层、复合涂层。热障涂层,作为一种表面改性中的涂层材料,具有优异的抗氧化性能以及长期服役性能。当应用于TiAl基合金表面时,热障涂层能够有效提升合金的高温抗氧化性能。但两者结合也存在如下问题,热生长氧化物的过度生长导致界面失效,以及涂层与基体元素互扩散严重,导致热障涂层/TiAl合金体系长期服役性能减弱。本文归纳并分析了TiAl基合金的高温氧化行为,分别从整体合金化以及表面改性两个方面综述了TiAl基合金高温防护的影响因素和作用机理,分析了热障涂层应用在TiAl合金表面所面临的问题并提出了改进方案,以期为提高TiAl基合金的抗高温氧化性能及发展热障涂层/TiAl合金体系提供参考。
Since 1970s,TiAl-based alloys have been used as a new lightweight high temperature structure candidate material because of their low density,high specific strength,ablative resistance,and good high-temperature mechanical properties.With the deepening of research on various strengthening and toughening measures,the problem of room temperature brittleness of TiAl-based alloys has been gradually solved.TiAl-based alloys have been successfully applied to aero-engine blades,aerospace vehicle skins,rudder wings,automobile exhaust valves,etc.However,the lack of high-temperature oxidation resistance of TiAl-based alloys limits their application as high-temperature components.At present,the high-temperature oxidation resistance of TiAl-based alloys is mainly improved by two methods:integral alloying and surface modification.Integral alloying is to add Nb,Si,Mo,W,rare earth and other alloying elements to the alloy,which promotes the formation of a dense oxide scale on the surface of the alloy and improves the adhesion between the oxide scale and the substrate.Surface modification mainly includes surface alloying and surface coating.Surface alloying technology generally includes thermal diffusion,ion implantation,pre-oxidation,laser surface alloying and so on.Surface coating technology is to use different kinds of coatings to improve the surface properties of the substrate,such as Ti-Al-X systemcoating,MCrAlY thermal barrier coating,ceramic coating,composite coating.Thermal barrier coating,as a coating material in surface modification,has excellent oxidation resistance and long-term service performance.When applied to the surface of TiAl-based alloy,it can effectively improve the high-temperature oxidation resistance of the alloy.However,the combination of the thermal barrier coating and TiAl-based alloys also has the following problems.The excessive growth of thermal grown oxides leads to interface failure,and the elements interdiffusion between the coating and the substrate is serious,resulting in the long-term service performance of the thermal barrier coating/TiAl-based alloy system is weakened.In this paper,the high-temperature oxidation behavior of TiAl-based alloys is summarized and analyzed.The influencing factors and mechanism of high-temperature protection of TiAl-based alloys are reviewed from two aspects of integral alloying and surface modification.The problems faced by the application of thermal barrier coatings on the surface of TiAl alloys are analyzed and the improvement scheme is proposed,in order to provide a reference for improving the high-temperature oxidation resistance of TiAl alloy and developing thermal barrier coating/TiAl alloy system.
作者
张业飞
江海涛
田世伟
张思远
李冲
ZHANG Yefei;JIANG Haitao;TIAN Shiwei;ZHANG Siyuan;LI Chong(National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing,University of Science and Technology Beijing,Beijing 100083,China;Luoyang Ship Materials Research Institute,Luoyang 471026,Henan,China)
出处
《材料导报》
北大核心
2025年第4期154-163,共10页
Materials Reports
基金
国家自然科学基金(52201035)。
关键词
TIAL基合金
热障涂层
抗氧化性能
整体合金化
表面改性
TiAl-based alloy
thermal barrier coating
oxidation resistance
integral alloying
surface modification
