Effect of Addition of Grain Refiner and Modifier on Microstructural and Mechanical Properties of Squeeze Cast A356 Alloy

Abstract

Al-Si alloy of grade A356 is widely used in several industries such as automobile, aerospace, defense, and others owing to its low density as well as the combination of other properties such as high strength, excellent castability, excellent thermal conductivity, good corrosion resistance, and good wear/abrasive resistance. In previous studies, the mechanical properties of gravity die-cast Al–Si alloys were found to be improved by the addition of grain refiners such as boron and titanium and also with the addition of modifiers such as strontium. Squeeze casting is pressure-assisted casting process and has been found to improve the mechanical properties of Al alloys. In the current study, the effect of the addition of Al-Ti-B alloys used with the purpose of grain refinement as well as the effect of combined additions of Al-Ti-B and two Sr levels used with the purpose of microstructural modification in squeeze cast Al–Si alloy A356 are investigated. The microstructure developed in various alloy compositions of squeeze cast alloys and the mechanical properties are studied. The effect of T6 solution heat treatment on the squeeze cast alloys is also analyzed. The addition of grain refiner and modifier helped in improving the mechanical properties of the alloy and further heat treatment helped in increasing the properties of the alloy. © 2022, The Indian Institute of Metals - IIM.