In order to investigate the effect of load frequency on the fatigue strength and fracture mechanism of a nickel-base superalloy, Inconel 718, fatigue tests were carried out under an ultrasonic frequency (19.5kHz) in ambient air environment. The results were compared with those obtained under conventional rotatary bending fatigue at a frequency of 50 Hz. Fatigue strength increased at ultrasonic frequency, which is mainly caused by the suppression of crack initiation and its growth at the early stage. Under both ultrasonic and rotary bending fatigue tests, most of fatigue life consumed in the growth of a crack smaller than 1 mm. In the ultrasonic fatigue, intergranular and cleavage crack propagations were observed in addition to striation, which was a dominant fracture mechanism in the conventional fatigue.
|Number of pages||7|
|Journal||Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - Mar 25 2003|
陳強, 皮籠石紀雄, 西谷弘信, 大坪謙一, 王清遠, & 近藤英二 (2003). Ni基超合金の超音波疲労特性. Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 69(679), 626-632. https://doi.org/10.1299/kikaia.69.626