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.
|Translated title of the contribution||Effect of Oxide Films on a Fatigue Crack Initiation and its Early Growth of Ni-Base Super Alloy|
|Number of pages||6|
|Journal||Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - Apr 25 1998|