Investigation on Mechanical and Machinability Properties of Aluminium Metal Matrix Composite Reinforced with Titanium Oxide (TiO2) and Graphite (Gr) Particles

Abstract

This research paper deals with the preparation process and testing of metal matrix composites comprising Aluminium alloy (Al 6061) as the base metal and Titanium oxide (TiO₂) and Graphite (Gr) as reinforcements. Due to their high specific strength, superior malleability, lightweight, stiffness   and excellent resistance to corrosion, oxidation and wear, the aluminium metal matrix composites are preferred in the automobile and industrial sectors for component manufacturing. No work reported on machinability properties of Titanium oxide (TiO₂) and Graphite (Gr) reinforced aluminium composites so far. This study prepared and studied samples composed of variable proportions of titanium oxide and graphite. The samples were prepared using the stir casting method. While stirring, the required additives were added to the molten aluminium mixture. To perform the tests, the samples were prepared according to standard dimensions after solidification. The mechanical properties of the prepared composite were examined using various test procedures, such as strength and hardness. Scanning electron microscopy was used to examine the microstructure of the test composite samples. The EDAX test confirmed the presence of graphite and Titanium oxide in the aluminium based composite specimens. Furthermore, machining was done to study the cutting forces on the tool. The test results showed a significant impact of the reinforced materials on the mechanical and machinability properties of aluminium metal matrix composites. Gr decreases hardness, while TiO₂ increases it. TiO₂ and Gr reinforcements increase the tensile strength of Al 6061 composites. The addition of TiO₂ decreased the composite's elongation. The proof strength of 2 % Al6061 was high, however it decreased with 3 % Gr and increased with TiO₂ reinforcement. Reinforcements increase cutting forces during machining; when comparing the machining of Al 6061 to that of 3 % Gr and 5 % TiO₂, a 50 % increase in cutting forces is noticed. However, excessive reinforcements may reduce cutting forces due to poor matrix-reinforcement adhesion.

HIGHLIGHTS

The mechanical and machinability properties of aluminium metal metrics reinforced with Titanium oxide (TiO₂) and graphite (Gr) have not been reported so far in the literature. In this study, aluminium based composites reinforced with variable proportions of titanium oxide and graphite were prepared and studied. The fabrication process was done by stir casting by adding the required additives into the molten mixture of aluminium, followed by continuous stirring. The solidified samples were cut according to the standard dimensions and various test procedures were conducted to examine the mechanical and machinability properties of the prepared composites. Gr reduces hardness, whereas TiO₂ enhances it. TiO₂ and Gr reinforcements boost Al 6061 composite tensile strength. TiO₂ addition reduced elongation of the composite. 2 % proof strength of Al 6061 was strong, however it dropped with 3 % Gr and rose with TiO₂ reinforcement. Reinforcements results higher cutting forces while machining, however excessive supplements lower cutting forces may be due to poor matrix-reinforcement bonding.

GRAPHICAL ABSTRACT