Mechanism of Crack Initiation Induced by Oxide-layer Cracking in High-Temperature Fatigue of the Nickel Base Single Crystal Superalloy CMSX-2.
Mechanism of Crack Initiation Induced by Oxide-layer Cracking in High-Temperature Fatigue of the Nickel Base Single Crystal Superalloy CMSX-2.
复制标题
镍基单晶高温合金CMSX-2高温疲劳中氧化层裂纹诱发裂纹萌生机理。
DOI：
10.2472/jsms.52.132
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
A. Wada
中科院分区：
文献类型：
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作者：
N. Tada;R. Ohtani;A. Wada
使用第一代镍基单晶高温合金CMSX-2的光棒试样在1273K下进行疲劳试验。试验后用扫描电子显微镜仔细观察试件及母材表面的氧化层。通过观察表明，CMSX-2高温疲劳裂纹萌生主要是由试件表面形成的氧化层开裂引起的。比较不同应力应变波形的试验结果，发现满足以下两个条件时，氧化层容易产生裂纹。第一个时间是氧化层形成的足够时间，因为裂纹发生在较厚的氧化层中，并且裂纹继续在母材内部生长。第二个条件是氧化层形成后存在拉伸应变。脆性氧化层很容易因以下拉伸载荷而破裂。此外，观察到的变化
Fatigue tests were conducted at 1273K using smooth bar specimens of the first-generation nickel-base single crystal superalloy CMSX-2. Oxide-layer on the surface of the specimen and the base metal were carefully observed by means of scanning electron microscope after the tests. It was clarified by the observation that crack initiation in hightemperature fatigue of CMSX-2 was mainly brought about by cracking of the oxide-layer which was formed on the surface of the specimen. Comparing the results obtained from the tests with different stress and strain waveforms, cracking of the oxide-layer found to be easily occurred when the following two conditions are satisfied. The first one is sufficient time for the formation of oxide-layer since cracking occurred in thick oxide-layer and the crack continued to grow inside the base metal. The second condition is that there is tensile-going strain after the formation of oxidelayer. The brittle oxide-layer was easily cracked by the following tensile loading. Moreover, there observed change in