Thermochimica Acta, Vol.589, 174-182, 2014
Evaluation of formation of intermetallic compounds in Al2024 alloy using thermal analysis technique
The aim of this research is to determine intermetallic compounds formed in Al2024 alloy. The effect of cooling rates on solidification characteristics of intermetallic phases such as, nucleation and growth temperature, nucleation time and solid fraction have been determined via first derivative curve. The range of cooling rates used in this investigation is between 0.4 and 17.5 degrees cs(-1). Thermal analysis was used to plot cooling curves and its derivative curves. Also, solid fraction versus time is plotted based on Newtonian technique. Microstructural evaluation and energy dispersive X-ray were used to identify intermetallic phases and their chemical composition. Formation of intermetallic compounds was interpreted through comparing the EDS analysis, binary and ternary diagrams, and the reactions detected from cooling curves. The results showed that nucleation and growth temperature of intermetallics was decreased by increasing of cooling rate. Also, the time intervals for the formation of intermetallic compounds were reduced. (C) 2014 Elsevier B.V. All rights reserved.