Micro-Structural Observation on Fatigue Fracture of Metals

抄録

It has been micro-structurally studied why the fatigue fracture of metals appears smooth and shelly ; white or black. The study has revealed that the fatigue fracture, initially rough, becomes smooth under repeated stress ; the metal dust produced is sintered, and in the case of high-carbon steel quench-hardened, under friction heat, into a very hard material. In this process, if air enters into the crack, the color of fracture surface will turn to black owing to the influence of friction heat ; otherwise, it would be white.