Evaluation of Fatigue Damage on Stainless Steel by EBSD method and Atomic Force Microscopy

摘要

Electron backscattering diffraction (EBSD) method and atomic force microscopy (AFM) were utilized to investigate the fatigue crack initiation and early propagation behavior in stainless steel, SUS316NG, under combined axial and torsional loading. The results show that fatigue crack initiated from grain boundaries regardless of the loading mode. EBSD analysis and AFM observation indicate that mismatch strain at those grain boundaries is larger due to the crystallographic orientation of the adjacent grains. Crack initiation and early propagation behavior are considered to be explainable based on the microscopic analysis by EBSD and AFM in combination with macroscopic fracture mechanics.