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Advances in Materials Science and Engineering
Volume 2015, Article ID 457384, 8 pages
http://dx.doi.org/10.1155/2015/457384
Research Article

Properties of GH4169 Superalloy Characterized by Nonlinear Ultrasonic Waves

1School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
2College of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144, China

Received 26 December 2014; Revised 28 January 2015; Accepted 28 January 2015

Academic Editor: Jainagesh A. Sekhar

Copyright © 2015 Hongjuan Yan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The nonlinear wave motion equation is solved by the perturbation method. The nonlinear ultrasonic coefficients β and δ are related to the fundamental and harmonic amplitudes. The nonlinear ultrasonic testing system is used to detect received signals during tensile testing and bending fatigue testing of GH4169 superalloy. The results show that the curves of nonlinear ultrasonic parameters as a function of tensile stress or fatigue life are approximately saddle. There are two stages in relationship curves of relative nonlinear coefficients β′ and δ′ versus stress and fatigue life. The relative nonlinear coefficients β′ and δ′ increase with tensile stress when tensile stress is lower than 65.8% of the yield strength, and they decrease with tensile stress when tensile stress is higher than 65.8% of the yield strength. The nonlinear coefficients have the extreme values at 53.3% of fatigue life. For the second order relative nonlinear coefficient β′, there is good agreement between the experimental data and the comprehensive model. For the third order relative nonlinear coefficient δ′, however, the experiment data does not accord with the theoretical model.