Effects of T6 Heat Treatment on Mechanical Properties of A356 Alloy Castings Prepared Under Oscillatory Conditions

Abstract Experiments have been conducted at 10 μm amplitude in frequency of oscillation range of 0-400Hz. Experiments have been carried out at two solutionising temperature 515 °C and 540°C for four hour and quenched in warm water of temperature 60°C and aging temperatures 160°C for four hour. The effect of mold oscillation during solidification and T6 heat treatment on microstructure, tensile properties and hardness were. The results show that percentage increase due to mold oscillation intensile strength, yield strength, elongation and hardness are 32% ,18%, 41.6% and 36.5% respectivelyand decrement in grain size is up to49%as compared to as cast without oscillation.Tensile strength,percentage elongation and hardness were improved further as compared to that of as cast due to heat treatment. Combined effect of moldoscillation and heat treatment on tensile strength, yield strength elongation and hardness are observed and it was found that these increased by 37% ,88%, 170% and 75% respectively and decrement in grain size was up to58%.Improvements in the properties are attributed to grain refinement of oscillatory prepared casting with heat treatment at 400Hz frequency, 540°C temperature. Keywords:-Moldoscillation, Heat treatment, Microstructure, SEM, Grain Refinement