INFLUENCE OF GRAIN REFINER AND MODIFIER ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A356 ALLOY

摘要

In the research work presented here, investigations were carried out to find the effect of grain refinement (by Al- 3Ti and Al-3B) and modification (by Al-10Sr) of A356 alloy. The effect was studied on the microstructure and mechanical properties of A356 alloy, which strongly dependent on the grain refinement and modification. The present result shows that a reduction in the size of ?-Al dendrites, modification of eutectic Si and improvement in the mechanical properties were observed with the addition of grain refiner and modifier either individual addition or in combination. The change in the microstructure from coarse columnar ?-Al dendrites to fine equiaxed dendrites and plate like eutectic silicon to rounded particles leads to improved mechanical properties. Metallographic studies reveal that the structure changes from coarse columnar dendrites to fine equiaxed one on the addition of grain refiner and plate like eutectic silicon to fine particles on addition of modifier.