Combining Differential Scanning Calorimetry and Cooling-Heating Curve Thermal Analysis to Study the Melting and Solidification Behavior of Al-Ce Binary Alloys

Abstract

Two common techniques of thermal analysis, Differential Scanning Calorimetry (DSC) and Cooling/Heating Curve Thermal Analysis (CCTA), based on different signal collected and utilizing samples with a weight difference of three orders of magnitude, were used to assess the solidification and melting behavior of Al-Ce binary alloys, containing from 5 to 20 wt. % Ce. Thermal analysis was accompanied by microscopic observations of solidified structures. For heating/cooling rates of 0.2–0.4 °C/s, temperatures of eutectic transformation L ↔ Al + Al11Ce3 in the Al-10Ce alloy along with additional proeutectic reactions L ↔ Al in the Al-5Ce hypoeutectic alloy and L ↔ Al11Ce3 in Al-15Ce and Al-20Ce hypereutectic alloys, were determined. Although there was a general agreement in major transformations, registered by DSC and CCTA during melting and solidification, differences in the reaction temperature determined exceeded the typical measurement errors for each technique. In addition, DSC and CCTA exhibited differences in detecting some proeutectic reactions and minor non-equilibrium effects, accompanying the eutectic transformation. Some factors that could contribute to differences observed and their implications for engineering practice were discussed.