The Effect of Mechanical Vibration on Casting Properties of Grain Refined A356 Alloy

Abstract

In this study, it was aimed to have the desired microstructure at low cost (fine and spherical) of aluminum alloys which have a wide usage in engineering materials and a wide variety of production methods. Al5Ti1B was added to the A356 aluminum alloy melted in a 700 °C resistive furnace with Ti content of 0.1, 0.2 and 0.3% by weight. Casting was performed on a 20, 10 and 5 mm cross-section metal mold placed on a vibration table producing a mechanical vibration of 50 Hz fixed frequency and 1.5 mm amplitude, vibration and non- vibration. Microstructural investigations on the cross-sections of the final casting products were carried out in two stages. In the first step, the distance between the secondary dendrite arms (SDAS) and the length of the secondary dendrite arms (SDAL) were measured on the images taken by optical microscope. In the second stage, EDS analysis was performed by SEM. Hardness measurements of the samples were made by Brinell method and the relationship between the microstructure and hardness values was tried to be revealed. SDAS and SADAL values decreased due to Ti content and section thickness. Accordingly, hardness tends to decrease as it progresses from thin section to thick section.In this study, it was aimed to have the desired microstructure at low cost (fine and spherical) of aluminum alloys which have a wide usage in engineering materials and a wide variety of production methods. Al5Ti1B was added to the A356 aluminum alloy melted in a 700 °C resistive furnace with Ti content of 0.1, 0.2 and 0.3% by weight. Casting was performed on a 20, 10 and 5 mm cross-section metal mold placed on a vibration table producing a mechanical vibration of 50 Hz fixed frequency and 1.5 mm amplitude, vibration and non- vibration. Microstructural investigations on the cross-sections of the final casting products were carried out in two stages. In the first step, the distance between the secondary dendrite arms (SDAS) and the length of the secondary dendrite arms (SDAL) were measured on the images taken by optical microscope. In the second stage, EDS analysis was performed by SEM. Hardness measurements of the samples were made by Brinell method and the relationship between the microstructure and hardness values was tried to be revealed. SDAS and SADAL values decreased due to Ti content and section thickness. Accordingly, hardness tends to decrease as it progresses from thin section to thick section.