X-Ray Microtomography Investigation of the Effect of Ba Additions on the Microstructure of Partially Remelted Al-4%Cu Alloys
The aim of this work is to study by X-Ray microtomography carried out at ESRF Grenoble the microstructure of an Al-4wt%Cu alloy which was previously cold rolled to obtain globules of the solid phase upon heating in the semi-solid range. Since this process produced entrapped liquid in the globules, 3D quantification of this liquid was performed. Moreover, the influence of the addition to the alloy of a small amount of Ba, which has been shown to decrease the contiguity between the solid globules as a consequence of the decrease of the solid-liquid interfacial energy σsl, was investigated. It is in particular shown that the amount of entrapped liquid is much larger in the Ba-containing alloy in agreement with the reduction of σsl, whereas the size of the liquid pockets is similar. In addition characterization of the interglobular liquid shows that the interface area between this liquid and the solid per unit volume is larger for the alloys containing Ba in agreement with previous observations carried out on 2D sections. The influence of strain during cold rolling is also reported but it is shown to have a quite limited influence on the previous parameters.
G. Hirt, A. Rassili, A. Bührig-Polaczek
S. Terzi et al., "X-Ray Microtomography Investigation of the Effect of Ba Additions on the Microstructure of Partially Remelted Al-4%Cu Alloys", Solid State Phenomena, Vols. 141-143, pp. 475-480, 2008