A Study on Fatigue Crack Propagation Properties Using the X-Ray Diffraction Method

Abstract

This study evaluated fatigue crack growth characteristics, Besides consider compressive residual stress effect and verified the most suitable shot peening velocity. Fatigue crack growth delay effect was compressive residual stress, but over peening did action projecting velocity that accelerate fatigue crack growth rate. X-ray diffraction technique according to crack length direction was applied to fatigue fractured surface. Fracture mechanics parameters could be estimated by the measurement of X-ray parameters, and the fractography observation was performed using a scanning electron microscope (SEM) for fatigue fracture surface. As the shot peening velocity increases, striation width increased. The changes in X-ray material parameters described above are directly related to the process of fatigue until the initiation of fatigue crack and X-ray diffraction pattern is thought that failure prediction with stress distribution is possible.

Experimental and numerical investigation on shot peening of low alloy steel

“…In addition, another application of shot peening is to restore a material which exhibits micro cracks and extend its useful life. A crack (fatigue fracture) firstly appears on the surface of the material during operation and then propagates into the bulk [14][15][16][17][18][19][20]. Therefore, the presence of compressive stresses induced by the shot peening process inhibits the crack formation and its propagation thereby improving the fatigue life.…”