en Research Paper Research Paper <div style="text-align: justify;">The influence of melt superheating treatment on the solidification characteristics and microstructure of Al&ndash;20%Mg₂Si in-situ composite has been investigated. The results revealed that melt superheating temperature has a significant effect on solidification parameters and morphology of primary Mg₂Si particles. Solidification parameters acquired using cooling curve thermal analysis method, indicate that both nucleation temperature and nucleation undercooling of primary Mg₂Si particles increase by increasing melt superheating temperature, while recalescence undercooling decrease under the same condition. Also, based on the microstructural evaluations, melt superheating treatment can refine primary Mg₂Si particles and alter their morphology from dendritic shape to more spherical shape and the eutectic microstructure of a-Al + Mg₂Si becomes finer and the distance between eutectic layers becomes smaller.<br> &nbsp;</div> Al–20%Mg2Si in-situ composite,melt superheating treatment,cooling curve thermal analysis,microstructure,solidification 1 9 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-132-4&slc_lang=en&sid=1 Saeed G. Shabestari shabestari@iust.ac.ir 1800319475328460014729 1800319475328460014729 Yes Professor of Materials EngineeringIran University of Science and Technology (IUST) Sahar Ashkvary 1800319475328460014730 1800319475328460014730 No School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran, Iran Farnaz Yavari 1800319475328460014731 1800319475328460014731 No School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran, Iran