Ultrasonic attenuation in textured polycrystalline materials: A framework for understanding competition between grain morphology and texture.

This paper investigates the competing mechanisms of grain morphology and crystallographic texture on the anisotropy of ultrasound propagation in polycrystalline materials. Electron backscatter diffraction (EBSD) analysis of the Electron Beam Powder Bed Fusion (E-PBF) fabricated SS316L samples reveals the presence of microstructural anisotropy induced by grain morphology and crystallographic texture. Based on finite element simulations, we demonstrate that ultrasonic attenuation is highly sensitive to microstructural anisotropy and further elucidate how grain morphology and texture interact to influence attenuation, demonstrating that texture becomes a dominant factor once its intensity surpasses a critical threshold. Immersion ultrasonic measurements were carried out to demonstrate the applicability of the proposed mechanisms in industrial applications. These insights provide a foundation for cost-effective and facile ultrasonic microstructural characterization in polycrystalline materials and support the development of nondestructive evaluation tools for quality assurance.