Improvement of surface integrity by ultrasonic vibration cutting and evaluation of fatigue properties

Abstract

Compressive residual stress on material surfaces leads to the improvement of fatigue resistance. However, cut surfaces generally have weak tensile residual stress, instead of the expected high compressive residual stress. In this study, high compressive residual stress exceeding -1000MPa was generated on the cut surface by appropriately combining ultrasonic vibration and changing the shape of the cutting edge. In addition, the surface hardness increased with increasing compressive residual stress on the cut surface. Fatigue testing showed that the improvement of the surface integrity contributed markedly to improvement of material fatigue resistance.