Measurement of Residual Stress in Thin-Sized Steel Wires by Using Focused Ion Beam and Digital Image Correlation Method

The residual stress in axial direction of the steel wires has been measured by using a method based on the combination of the focused ion beam (FIB) milling and digital image correlation (DIC) program. The residual stress is calculated from the measured displacement field before and after the introduction of a slot along the steel wires. The displacement is obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot is introduced by FIB milling with low energy beam. The experimental procedures are described and the feasibilities are demonstrated in steel wires fabricated with different conditions.