MECHANICAL PROPERTIES AND PHASE EVOLUTIONS IN HEAT-TREATED CAST Al-SiC-TiO2 METAL MATRIX COMPOSITES

Ebenezer, Afolabi Ayodeji and Aramide, Fatai Olufemi and Adediran, A.A and Popoola, Abimbola Patricia (2021) MECHANICAL PROPERTIES AND PHASE EVOLUTIONS IN HEAT-TREATED CAST Al-SiC-TiO2 METAL MATRIX COMPOSITES. Journal of Materials in Civil Engineering, 56 (1). pp. 235-246. ISSN 19435533, 08991561

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Abstract

The effect of heat treatment with an addition of titania on the phase development and mechanical properties of sand casted Al-SiC-TiO2 metal matrix composite was investigated. The standard samples dimensions for tensile properties, wear and hardness were prepared. These samples were heat treated at different temperature of 180°C to 220°C without solution treatment. The samples were held at the heat treatment temperature for an hour after which they were allowed to cool in the air. Thereafter, samples were subjected to various mechanical and wear tests, respectively. The phases evolved due to heat treatment of the samples were examined using X-ray diffractometry. It was observed that the increase in heat treatment temperature of samples leads to the formation of precipitates within the aluminium matrix composite reinforced with SiC. The addition of 5 % titania inhibits the formation of aluminium silicon carbide phases in preference to SiO2 and TiO2 . The increase in heat treatment temperature leads to the formation of precipitates like TiSi2 , Si11.4TiO24.4, TiC, Al2 O3 and buckminsterfullerene C70 within the aluminium matrix composite. The addition of 10 % titania leads to the development of precipitates like Al5 Ti3 and Ti-rich oxides with the aluminium matrix. At 220°C, alumina was formed within the metal aluminium matrix and no trace of SiC was found. All the samples have low wear loss but the heat treated at 180°C sample (A) has the lowest wear loss. The heat treatment of the sample without solution treatment has impact on the phase development in the samples. It gives rise to the development of precipitates in the samples which affects the hardness and other mechanical properties. The addition of SiC and TiO2 to aluminium matrix makes the sample harden. Sample A heat treated at 200°C have the highest hardness.

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