Fast Synchrotron X‐Ray Tomography of Dynamic Processes in Liquid Aluminium Alloy Foam

Abstract

Series of fast synchrotron X‐ray tomographies are taken continuously at a rate of up to 5 Hz, while aluminium alloy precursors are foamed in an X‐ray transparent setup for several minutes using infra‐red (IR) lasers for heating. The entire foaming process from the solid precursor to the expanded liquid foam is captured. The analysis of the sequence of tomographies is done with an emphasis on nucleation and bubble growth. In early stages of foaming, bubble and crack formation and evolution are observed. We analyze the nucleation stage and obtain quantitative results for the number of nucleation centers and their distribution and derive the nucleation rate as a function of time.