抄録
The author discusses the mechanism of the fracture of metal under a cyclic stress. He paid a special attention to the relation between the repeated stress vs. slip-phenomenan, slip-phenomenan vs start of fracture, growth of fracture vs. crystalline boundary, etc. The specimens used were a sheet of Super-Duralumin for the preliminary test and α-Brass for the final test. The surface of these specimens were polished and etched before setting them on Sehenck's Vibratory Endurance Testing Machine. Thus, the author observed the structural change of the specimen by microscope at the various stages of stress and the stress due to number of repetitions of testing.
