Evaluation of formation of intermetallic compounds in Al2024 alloy using thermal analysis technique

• Investigation on various intermetallics formed during solidification of Al2024 using thermal analysis.
• Study the effect of cooling rate on solidification parameters of intermetallics in Al2024.
• Using wide range of cooling rates to simulate solidification condition of Al2024 alloy.
• Investigation on nucleation and growth of intermetallics at cooling rate used in DC casting.
• Presenting a correlation between intermetallics nucleation temperature and cooling rate in Al2024.

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 °C s−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.