INVESTIGATION OF MECHANICAL PROPERTIES IN DYNAMIC SOLIDIFICATION USING CONFORMED COOLING TECHNIQUE

Abstract

Aluminum alloys are the most widely used alloys in the current era. Their applications range from high speed air crafts to domestic utensils. These are light weight but they are not as strong as steel. Many processes are used to increase their strength such as: addition of grain refiner, mechanical, ultrasonic or electromagnetic vibrations during solidification and squeeze casting. The purpose of this thesis is to propose a framework for eliminating or minimizing defects in casting process as well as increasing strength and hardness without performing separate heat treatment process. In this research mechanical vibrations are applied to the aluminum 2024 alloy in the range of 15Hz to 45Hz frequency and 0.5g to 1.5 acceleration at different pouring and die temperatures. Taguchi design of experiments approach was used to perform experiments and ANOVA was applied to get the results. Best results are obtained at 750C pouring temperature, 150C die temperature, 45Hz frequency and 1.0g acceleration which is then compared with the as-cast sample. It is observed that non-dendritic microstructure can be obtained by applying mechanical vibrations to the mould during solidification. The average grain size is reduced by 40.6%, hardness and ultimate tensile strength are improved by 13.5% and 10.6% respectively