Acoustic nonlinearity parameter induced by extended dislocations

Xiang Gao, Jianmin Qu

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Excess acoustic nonlinearity is a signature of microstructural defects on a propagating ultrasound. By measuring the excess acoustic nonlinearity parameter, defect characteristics can be inferred nondestructively through ultrasonic techniques. To this end, proper models are needed to relate the excess acoustic nonlinearity parameter with defect characteristics. In this study, an analytical model for extended dislocations is developed that relates the excess acoustic nonlinearity parameter with characteristics of the extended dislocation including dislocation density, stacking fault energy, and equilibrium distance between the two partial dislocations that form the extended dislocation. According to this model, the excess acoustic nonlinearity parameter induced by extended dislocations consists of a stress-independent term and a stress-dependent term. Both terms are scaled with (Lchar/b)n, where Lchar is the equilibrium distance between the two partials, b is the magnitude of Burgers vector, and n is 3 and 4 for the stress-independent and stress-dependent terms, respectively. The model will be useful for interpreting results from ultrasonic nondestructive evaluation of material defects.

Original languageEnglish
Article number125102
JournalJournal of Applied Physics
Volume124
Issue number12
DOIs
StatePublished - 28 Sep 2018

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