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Fatigue Strength of Functionally Graded Thermal Barrier Ceramic Coatings Subjected to Thermal Cycling under Gradient Temperature

梯度温度下热循环功能梯度热障陶瓷涂层的疲劳强度

基本信息

批准号：
06452147
负责人：
MUTOH Yoshiharu
金额：
$ 4.86万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

Surface modification techniques, such as thermal barrier coatings and protective coatings are key technology to develop next generation advanced gas turbines. As a part of program to develop the high performance coating systems for advanced gas turbines, the high temperature strength of the advanced materials with surface modifications has been studied in this research program. The conclusions obtained are summarized as follows :(1) A new fatigue test machine which can simulate the service condition of turbine blades and vanes was successfully produced.(2) Thermal fatigue tests of conventional two-layr NFGM coating specimens and a functionally gradient material (FGM) coating specimens were carried out. Damage process of the functionally graded thermal barrier coatings during the thermal cycling was qualified. The degradation of thermal barrier function of the FGM was also qualified.(3) The effect of the functionally graded thermal barrier coatings on the thermal fatigue strength of the … More advanced materials with ceramic coatings surface damage strength was quantitatively evaluated by the thermal cycling test in vacuum.(4) The fatigue fracture of the Ni-base superalloy, IN 738LC,coated with the so-called M-Cr-Al-Y alloys by low pressure plasma spraying was studied and clarified at high temperature in vacuum condition, compared with that of the substrate alloy, IN 738LC.The fatigue crack propagation process was also made clear from the investigation employing the special equipment with cyclic loading stages which fit within the scanning electron microscope. Special focus was paod on the fatigue crack growth behavior in the coated layr and the dependence of the MCrAlY alloy systems, as well as near the interface.(5) The effect of aluminide coating on the high-cycle fatigue strengths of Ni-base superalloys was clarified at room temperature and 800 ﾟC in vacuum, in comparison with those of the substrates. Based on the measurement of a critical strain above which brittle cracking appeared at the aluminide coating, a simple method which can provide a reasonable estimation corresponding with the experimental life, was proposed. Less

热障涂层和防护涂层等表面改性技术是发展下一代先进燃气轮机的关键技术。作为开发先进燃气轮机高性能涂层系统计划的一部分，本研究计划对表面改性的先进材料的高温强度进行了研究。(1)研制了一台能够模拟涡轮叶片和叶片使用情况的新型疲劳试验机。(2)对常规双层NFGM涂层试件和一种功能梯度材料涂层试件进行了热疲劳试验。验证了功能梯度热障涂层在热循环过程中的损伤过程。功能梯度热障涂层对…热疲劳强度的影响通过真空热循环试验，定量评价了更先进的陶瓷涂层材料的表面损伤强度。(4)研究了低压等离子喷涂M-Cr-Al-Y合金涂层镍基高温合金IN 738LC的高温疲劳断口，并与基体合金IN 738LC在高温下的疲劳断裂进行了对比。重点研究了涂层中疲劳裂纹的扩展行为和MCrAlY合金系统以及界面附近的疲劳裂纹扩展行为。(5)研究了铝化物涂层对镍基高温合金在室温和800ﾟC真空条件下高周疲劳强度的影响，并与基材进行了比较。通过对铝化物涂层出现脆性开裂的临界应变的测量，提出了一种简单的方法，可以给出与实验寿命对应的合理估算。较少