Effects of electric pulse modification on liquid structure of Al-5%Cu alloy
(1. Faculty of Materials Science and Engineering, Liaoning University of Technology, Jinzhou 121001, China;
2. School of Metallurgical and Ecological Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
2. School of Metallurgical and Ecological Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
Abstract: The electric pulse modification (EP, EPM) of liquid metal is a novel method for grain refinement. The structure of EP-modified Al-5%Cu melt was characterized by high-temperature X-ray diffractometry. The results show that the Cu-containing Al clusters remarkably increase in the EP-modified melt, furthermore, these clusters in that case tend to contract due to the decrease of relevant atomic radius and the co-ordination number. This kind of liquid-phase structure leads to a more homogeneous Cu-rich phase distribution in the final solidification structure. Differential scanning calorimetry (DSC) tests indicate that the solidification super-cooling degree of the EP-modified liquid phase is 2.36 times that of the unmodified. These facts suggest that the atom cluster changes in EP-modified Al-5%Cu melt would disagree with that by EPM model previously proposed in liquid pure metal.
Key words: electric pulse modification; Al-Cu melt; atomic cluster; liquid structure