Mechanical properties of Al-Si alloys with snail shell powder as reinforced agent

This research aimed to increase the mechanical properties of Aluminum silicone (Al-Si) alloy by adding CaO as the reinforcement. This research involved powdered snail shell as the source of CaO for 0.05% from the 1.5 kg weight of Al-Si. This research used stir casting method where 1.5 kg Al-Si was melted in a furnace then added snail shell powder then stirred for 2 minutes. After, the liquid was poured into permanent cylindric metal moulds to form a tensile test specimen. The specimens then were mechanically tested to determine the tensile result, hardness test followed by microstructure test and fracture analysis. The result showed base material has 15,65 kg/mm2 tensile strength and reduction in the sample with 750℃ pouring temperature has the tensile strength of 9,34 kg/mm2 but improved in the samples with 800℃ has the tensile strength of 9,4 kg/mm2 and 850℃ pouring temperatures has the tensile strength of 13,76 kg/mm2. The highest tensile strength was found in the base material with the value of 15,65 kg/mm2 that had smaller dendrite, brittle fracture, and flat fracture that signified brittle fracture. But hardness tester showed increase, from base material and samples with temperatures 750℃ has the hardness tester of 74 HRB increase to sample with temperatures 800℃ has value 82,33 and sample with temperatures 850℃ has value 83,67. Based on the result it can be obtained that Al-Si alloy with the variation pouring temperature 850℃ is the best variation if applied to products that require high materia hardness, supported with the macro image that showed smaller and denser grains and had evenly distributed reinforcement with smaller dendrite structure.