[6A3] Material texture characterisation in metallic curved components using diffused ultrasound
M Png, M Lowe and B Lan
Imperial College London, UK
During the fabrication of any metal component, processes such as heat treatment could result in a preferred crystallographic orientation (texture) in the material, which defines the component’s material properties. To overcome the limitations posed by several state-of-the-art texture characterisation methods, Imperial College’s Non-Destructive Evaluation (NDE) Group has developed a bulk texture measurement method using immersion ultrasound. However, this immersion technique could only inspect raw material blocks with flat surfaces. This restrains inspection on components that tend to have a more complex geometry near the end of the manufacturing process and whose texture is more critical for real applications. This work proposes the use of diffused ultrasonic fields to reconstruct texture in metallic components with curved surfaces. With the aim of obtaining velocity values at different angles with high precision, preliminary velocity measurements using diffused fields will be shown. The results are calibrated against conventional coherent velocity measurements and a range of methods to improve the reconstruction quality are trialled, with various degrees of success. To aid the understanding of the wave diffusion process, a simulation model has also been developed and used to illustrate wave interactions with microstructures within the sample and to optimise the velocity measurements.
Keywords: ultrasonics, diffused fields, Green’s functions, crystallographic texture.
Keywords: ultrasonics, diffused fields, Green’s functions, crystallographic texture.
