Microstructure and mechanical properties of Al-Si cast alloy grain refined with Ti-B-Sr-Sc-Mg

Grain refinement plays a crucial role in improving characteristics and properties of aluminum (Al) alloys. Silicon (Si) is the major alloying element their because of superior casting characteristics. Generally Sronthium (Sr), Scandium (Sc) and Aluminium-Titanium-Boron (Al-Ti-B) master alloys were added to the Al alloys to grain refine the alloys. Sr and Sc are the most widely used and a very effective element for modifying the morphology of eutectic Si, while Ti-B is commonly present in the commercial grain refiners used for Al-Si alloys. In this investigation the Sc contents were chosen in ranging of 0.02 to 0.08 wt.%. The results showed that the most adequate microstructure was obtained from the alloy modified with amount of 0.02 to 0.08 wt.% of Sc modifiers. The dendrites of the cast binary alloy were seen to have significantly refined with the addition of Sc. Alloy with 0.02 wt% Sc content does not provide much grain refinement, but refines the primary dendrites of α with consequent diminution of dendrite arm spacing. Added Sc in Al-Si cast alloys has influenced on the grain refinement and improves the hardness and tensile stress of Al-Si cast alloys. Added 0.08 wt.% Sc gave the highest value for hardness and tensile stress. The value were 95.80 Hv and 399.4 MPa respectively. From this investigation, we can conclude that the addition of modifier and grain refiner will increase hardness and tensile stress of Al-Si cast alloy. From this investigation, we can conclude that the addition of modifier and grain refiner will increase the hardness and tensile stress value of Al-Si cast alloy.