Use of Time Resolved X-Ray Radiography to Measure Interdiffusion in Liquid Metals

1. Introduction Chemical diffusion (also named interdiffusion), originating from the fluctuations among different elements, is a common phenomenon in multicomponent liquid metals. The interdiffusion coefficients in liquid alloys control the liquid-solid transformation and are thus basic parameters for materials design from the melt. In this work, a novel X-ray radiography (XRR) technique (Fig.1) is developed to in situ measure interdiffusion in liquid alloys[1, 2]. With this in-situ method, we can accurately measure liquid diffusion coefficients directly in the liquid state without knowing the absolute diffusion time and without considering the solidification effect [2]. Particularly, XRR can also allow us to check for the buoyancy-driven convention effect in the liquid diffusion process. With this method, reliable interdiffusion data in Al-Cu and Al-Ni melts have been measured systematically [2, 3].