A New Strategy to Prevent The Undesirable High Temperature Fatigue Reduction due to Cellular Formation in Microstructurally-Controlled Ni-Base Superalloys : -For Refurbishment and Recoating Technology-

一种新策略，可防止微观结构控制的镍基高温合金中因气泡形成而导致的不良高温疲劳降低：-用于翻新和重涂技术-

基本信息

批准号：
12650072
负责人：
OKAZAKI Masakazu
金额：
$ 2.5万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Recently industrial gas turbine power plants have been the major baseload source of power for many countries. These applications require a highly reliable, long-term load mechine which can operate using cheap, available fuels. Nobody doubts that repair, recoating and refurbishment of the hot section components in service under extremely sever condition will be inevitable technology in very near future. Nevertheless, there has been no established method for these technologies yet. Main objective in this work is to get basic understandings on the refurbishment and rcoating technology of microstructurally-controlled Ni-base superalloys, from a viewpoint of material relaibility.At first the microstructural changes in a single crystal Ni-base superalloy, CMSX-4, and a directicnally-solidified alloy, CM247LC, are shown in this work. After a plastic straining at room temperature into these alloys to simulate several kinds of in-service damages, the re-heat treatments as a usual course of dama … More ge recovery process was performed at elevated temoeratures ranged from 1080℃ to 1300℃. A siginificant change in microstructure, or cellular formation, was found to occur, depending on the re-heat treatment temperature. It was also found that the change was quite anisotropic, being influenced by the strain field and the microsegregation in the material.Next the effect of the carried out at 950℃ in air at a frequency of 10 Hz under fully-reserved loading ratio, by means of an electro-hydraulic fatigue testing machine. The experiments indicated that once the cellular formation was reached, the fatigue strength was remarkably reduced : an indication of a serious role of the cellular formation was reached, the fatigue strength was remarkably reduced : an indication of a serious role of the cellular formation for recoating and refurbishment technology.Finally the method to reduce and prevent the above undesirable effect is shown. It was found by the fatigue tests that the application of the surface modification technique, or protective coating might be a promising method. It was suggested that the control of alloy composition of the coating could also be a useful technique to reduce the harmful effects. Less

最近，工业燃气轮机发电厂一直是许多国家的主要基本电源来源。这些应用需要一种高度可靠的长期负载机制，可以使用便宜的可用燃料运行。没有人怀疑在不久的将来，在极度严重状况下，在非常严重的条件下进行维修，重新饰演和翻新的服务部件将是不可避免的技术。然而，尚无针对这些技术的既定方法。这项工作的主要目的是从材料可靠性的角度来获得微观控制的Ni-base Superalloys的翻新和划分技术的基本理解。首先，单个Crystal Ni-Base Superalloy，CMSX-4的微观结构变化，CMSX-4，以及直接分析的Alloy，CM247LC，在此工作中显示。在室温下将塑料过滤入这些合金以模拟几种服务的损害后，将重新加热作为通常的Dama疗程……在较高的临时次数上进行了更多的GE恢复过程，范围从1080℃到1300°。根据重新加热的处理温度，发现了微观结构或细胞形成的毫无用处。还发现，这种变化是各向同性的，受应变场的影响和材料中的微层次的影响。在空气中以10 Hz的频率在完全保留的加载率下，在950℃进行的效果中，通过电溶剂 - 溶剂疲劳测试机。实验表明，一旦达到了细胞形成，疲劳强度就会显着降低：达到了细胞形成的严重作用的指示，疲劳强度大大降低：表明细胞形成的严重作用是重新载体和翻新技术的严重作用。降低和防止上述不可效应的方法。通过疲劳测试发现，表面修饰技术或保护涂层的应用可能是一种承诺方法。据建议，涂层合金组成的控制也可能是减少有害效应的有用技术。较少的