Prediction of Laser Irradiated Surface Properties by Eddy Current Method

Abstract

The laser surface modification poses two significant problems, namely, a) accurate determination of melt depth as the metallurgical and mechanical properties of the diffusion layer change with this depth and b) detection and characterization of defects within the modified surface. The objective of this work is to determine theoretically if eddy current method of nondestructive testing (NDT) is sensitive enough to determine changes in material properties, melt depth and defect parameters in surfaces modified by high energy laser beams. Using a finite element numerical analysis technique eddy current signals were predicted (absolute and differential probes) for different fusion zone geometries produced by a single laser pass. The results show that eddy current NDT techniques can be employed to determine the changes in properties and cracks in laser modified surfaces.