Tracking Hydrogen Microporosity Evolution During Solidification of Al–Cu–Li Alloy Using Multiscale Model and Synchrotron Radiation X-ray Radiography

In-situ observations of the evolution of hydrogen microporosity nucleation and growth during solidification of Al–Cu–Li alloys were conducted by using synchrotron X-ray radiography. The kinetic behavior of hydrogen microporosity and the mechanisms of nucleation and growth were investigated and verified by comparison with a multiscale model. Hydrogen microporosity was found to nucleate at temperatures between 610 °C and 622 °C during solidification and exhibited rapid growth between 565 °C and 610 °C, with growth rates around 3.2 μm/s. The evolution of hydrogen microporosity growth was best described by the Boltzmann function and displayed merging and ripening behavior. The average equivalent diameter (D¯_e) of hydrogen microporosity and hydrogen supersaturation (SS_H) followed the relationship D¯_e=23.96SS_H^−0.27. The evolution of 3D hydrogen microporosity during the solidification of Al–Cu–Li alloy was predicted by using a multiscale model. Simulation results agreed well with in-situ experiments, offering a predictive tool for optimizing the manufacturing process of Al–Cu–Li alloy products. Graphical Abstract: (Figure presented.)