摘要
随着各国对航空发动机推重比的要求日益提升,为满足高推重比的需求发动机涡轮进口温度持续增加,相应的,发动机所用热端材料的高温力学性能也需满足更高的标准。在650~1000℃范围内具有良好的高温力学性能的镍基高温合金,在发动机材料中约占40%,足见镍基高温合金在航空航天领域中的特殊地位。纵观镍基高温合金的发展史,良好的高温蠕变性能一直是研究者们追求的目标。航空发动机在服役过程中的高温蠕变会导致高温零部件产生过大的塑性变形,特别是当进一步提升涡轮进气口温度时,合金的蠕变性能无法满足严苛服役环境的矛盾将更加突出。例如,在高温环境下,温度只增加15℃,零件的蠕变寿命就会缩短一半。因此,为不断提升镍基高温合金的高温性能,向合金中添加难熔元素(如Re、Cr、Mo、Ta和W等),特别是添加Re元素时,镍基高温合金的蠕变性能大幅提升。但是,大量难熔元素加入镍基高温合金后,合金在服役过程中会大量析出拓扑密堆相,反而会危害合金的蠕变性能。长久以来,抑制拓扑密堆相的形成都是提升镍基高温合金蠕变性能的重要研究方向。
With the increasing requirements for aero-engine thrust-to-weight ratios in various countries,the turbine inlet temperature of engines continues to increase in order to meet the demand for high thrust-to-weight ratios.Accordingly,the high-temperature mechanical properties of hot-end materials used in engines also need to meet higher standards.Nickel-based superalloys with good high-temperature mechanical properties in the range of 650-1000°C account for about 40%of engine materials,which shows the special status of nickel-based superalloys in the aerospace field.Throughout the development history of nickel-based superalloys,good high-temperature creep properties have been the goal pursued by researchers.The high temperature creep of the aero engine during service will cause excessive plastic deformation of high temperature parts,especially when the temperature of the turbine inlet is further increased,the contradiction of the alloy's creep performance cannot meet the harsh service environment will be more prominent.For example,in a high-temperature environment,if the temperature is increased by only 15°C,the creep life of the part will be shortened by half.Therefore,in order to continuously improve the high-temperature performance of nickel-based superalloys,the addition of refractory elements(such as Re,Cr,Mo,Ta and W,etc.)to the alloy,especially when adding the Re element,the creep performance of the nickel-based superalloy is greatly increased.However,when a large number of refractory elements are added to the nickel-based superalloy,a large number of topologically close-packed phases will precipitate out during the service of the alloy,which will harm the creep performance of the alloy.For a long time,the suppression of the formation of topological close-packed phases has been an important research direction to improve the creep properties of nickel-based superalloys.
作者
张诗吟
ZHANG Shiyin(Institute of Solid Microstructure and Properties,Beijing University of Technology,Beijing,100022 China)
出处
《科技创新导报》
2020年第21期100-103,共4页
Science and Technology Innovation Herald
关键词
镍基高温合金
拓扑密堆相
蠕变性能
析出
Nickel-based superalloy
Topological close-packed phase
Creep properties
Precipitation
