3D Imaging of Liquid Film Migration in Aluminium Alloy after Brazing using Phase-contrast Tomography

Abstract

　An application problem when brazing aluminium is that molten braze alloy may penetrate into the bulk. This may, for example, increase the risk for reduced corrosion resistance and may in the long run lead to coolant leakages in heat exchangers. The phenomenon is poorly understood, which motivates a closer look using synchrotron radiation based 3D imaging. Through phase-contrast tomography at the BL14-B2 beamline at SPring-8 we have recorded 3D images of aluminium sheet materials with different stages of braze alloy penetration where the braze alloy penetration process can be visualized step by step. The characteristic signs of braze alloy penetration has been identified in the 3D images and the project has provided new perspectives on the braze alloy penetration process.