Document Type

Conference Proceeding


Review of Progress in Quantitative Nondestructive Evaluation

Publication Date



Denver, CO


This paper reports on a study of the effects of cold work induced by surface enhancement treatment on conductivity profiles in nickel-base superalloys, as part of the on-going efforts aimed at evaluating the feasibility of characterizing near-surface residual stress profiles in peened engine components using a swept frequency eddy current (SFEC) technique. The approach is based on the empirical piezoresistivity effect that correlates conductivity changes with residual stress, but recent studies have shown that conductivity changes induced by peening processes are also influenced by metallurgical factors such as cold work. In this study, conductivity deviation profiles were obtained by model-based inversion of SFEC signals from a set of aged Inconel 718 samples, which were either shot peened or laser shock peened to produce different residual stress and cold work profiles. The laser shock peened samples exhibit a larger increase in surface conductivity and deeper conductivity profiles, which are attributed to a smaller amount of surface cold work and deeper residual stress profiles created by laser shock peening than by shot peening.


Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

This article appeared in AIP Conference Proceedings 1511 (2012): 1219–1226 and may be found at

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American Institute of Physics




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