Dynamic Quantification of the Atom Rearrangement Behavior with Al-Mg 5052 Undercooling Liquid Film

The atom rearrangement behaviors along with the rapid solidification and high temperature oxidation of an interdendritic liquid (liquid film) with an arc spot-fused A5052 sheet were experimentally investigated in comprehensive terms of the solidification progress, concentration, and temperature by using high-speed breaking and breakage techniques. The latter is a new quenching method with an aqueous solution of surface-active agents to prevent the fractured section from the selective diffusion of Mg coupled with high temperature oxidation. Continuous liquid films of the fractured-section (solidification) layers were analyzed by XPS as well as fractography with FE-SEM . In a surfactant experiment, the results verified that the characteristic diffusion during oxidation occurred with the driving force being electrostatic attraction. Concerning the solidification behavior of rapidly solidifying columnar dendrite, the results of XPS measurements indicated that after a tip undercooling of about 25 °C the liquid solute concentration increased exponentially with decreasing temperature, while taking a solute concentration path below the T0 curve (in binary system analysis). The fractography was in qualitative agreement with the solute concentration result in terms of the mass balance by showing restricted lateral solidification progress.