Numerical analysis of intragrain precipitate influence on the linear scattering behavior

Abstract

Nondestructive evaluation using ultrasonic waves is commonly used to experimentally probe for the presence of defects (i.e. dislocations, precipitates, cracks) in complex metallic microstructures. Such defects and abnormalities are evidenced by monitoring the acoustic attenuation coefficient alpha. However, from a mathematical standpoint, the correlation between the microstructural behavior and the measured acoustic attenuation behavior is not yet explicit. The present work aims to assess the existence of statistical correlations between microstructural defects and acoustic attenuation. The effects of defect geometry, density, and geometrical arrangements (i.e. relative position) on acoustic attenuation are studied. To do so, the acoustic response of Fe-Cu single crystals containing 1% Cu precipitates with radii on the order of 2 nm is simulated by means of finite element analysis. Several thousand initial microstructures with random arrangement of precipitates are virtually tested using statistical methods, such as principal component analysis. Therefore, it is expected that a causal link can be made between the acoustic attenuation coefficient and the precipitates-induced microstructural behavior via the proposed numerical analysis.