Metal physics based model for predicting the influence of plastic cold-working on the acoustoelastic effect

Ultrasonic technology is a crucial non-destructive testing method in materials research and industry applications, widely used for detecting defects like pores and cracks, measuring residual stresses via the acoustoelastic effect, and determining surface roughness and dislocation density in metals. Building on Hughes and Kelly’s acoustoelasticity theory, which extends Murnaghan’s non-linear elasticity theory, this study investigates the propagation velocity of ultrasonic waves in relation to an plastic cold-working deformation state. Key models, including the Taylor equation and the Kocks–Mecking model, describe the relationship between dislocation density and macroscopic mechanical properties, elucidating the effects of plastic deformation. This research focuses on the impact of plastic deformation on the propagation velocity of ultrasonic waves and the acoustoelastic constant. By integrating theoretical models and experimental data, it establishes a mathematical framework for the acoustoelastic constant as a function of plastic strain. The study validates these models using experimental data, highlighting a quadratic relationship between wave velocity changes and plastic strain. The findings underscore the sensitivity of acoustoelastic constant to microstructural changes, offering valuable insights for monitoring and analysing material properties in industrial applications.