Effect of oxide films on a fatigue crack inititation and its early growth of Ni-base super alloy
Effect of oxide films on a fatigue crack inititation and its early growth of Ni-base super alloy
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氧化膜对镍基高温合金疲劳裂纹萌生及早期生长的影响
DOI：
10.1299/kikaia.64.839
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
E. Kondo
中科院分区：
文献类型：
--
作者：
N. Kawagoishi;Y. Ōzono;Qiang Chen;M. Goto;Hideho Tanaka;E. Kondo
对镍基高温合金Inconel 718进行了室温和300°C、500°C、600°C高温旋转弯曲疲劳试验，研究了高温表面氧化对疲劳裂纹萌生和早期扩展过程的影响。当应力水平较低时，高温下的疲劳强度高于室温下的疲劳强度。这种现象是由于在高温下，比几个晶粒尺寸小的裂纹的生长受到抑制，但较大的裂纹的生长得到加速。抑制小裂纹早期扩展的主要原因是在高温下试样表面形成氧化膜。
Rotating bending fatigue tests were carried out for Ni base super alloy Inconel 718 at room temperature and elevated temperatures of 300°C, 500°C and 600°C in order to investigate the effect of surface oxidation at the elevated temperatures on the fatigue crack initiation and its early growth process. The fatigue strength was higher at the elevated temperatures than at room temperature when stress levels were low. This phenomenon was caused from that the growth of a crack smaller than the size of a few grains was suppresed at the elevated temperatures, though the growth of a larger crack was accelerated. The main reason for the suppression of the early growth of a small crack was a formation of oxide films on the specimen surface at the elevated temperatures.