The Mechanical Properties of Al2O3-Reinforced Aluminum A356 with Grain Refiner Al-5Ti-1B Fabricated using the Stir Casting Method

Al2O3 reinforced aluminum A356 has been successfully fabricated using the stir casting method. The development of current technology requires a material that is light, strong, tough, and corrosion and wear resistant, in addition to various other advanced properties. A composite material was therefore developed. Composite materials can be used in a wide range of strategic sectors such as the automotive, military, aerospace, and electrical industries. This study aims to develop a composite material that consists of aluminum A356 as the matrix and micro Al2O3 as the reinforcement, with 8 wt% magnesium as the wetting agent with the addition of grain refiner TiB at 0; 0.01; 0.0347; 0.0362; 0.0622; and 0.0689 wt% using the stir casting method. The material characterization comprises tensile testing, hardness testing, wear testing, chemical composition testing (OES and XRD), and microstructure testing (OM, SEM, and EDX). The test results revealed that the addition of 0.0347 wt% TiB was capable of reducing the size and changing the shape of a long and coarse grain to become round and fine, thereby significantly increasing its tensile strength, hardness, and wear resistance, but decreasing the elongation and ductility.

Al2O3; Aluminum A356; Composite; Grain refiner TiB; Stir casting

The addition of Al2O3 particles and grain refiner TiB reduces grain size from 153.11 ?m to 78.61 ?m and changes the shape of elongated and coarse grains into equiaxed and fine grains that increase tensile strength, hardness, and wear resistance but also decrease elongation and ductility. The process is influenced by the mechanism of grain boundary strengthening, chemical composition, the size and shape of the grain, Al2O3 particle distribution, and porosity. The optimum addition of grain refiner TiB was obtained at 0.0347 wt% and 0.0362 wt%. Microstructure observations and XRD testing indicate the formation of aluminum, silicon eutectic, primary Mg2Si, binary Mg2Si, ternary Mg2Si, Al3Ti, and ?-Al5FeSi phase.

This research is supported by the University of Indonesia through its Research Grant Program, Hibah PITTA tahun anggaran 2017, Nomor: 767/UN2.R3.1/HKP.05.00/2017.

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