Effect of SiO2 Coating on Microstructure and Mechanical Behavior of Al-ABOw Composite Synthesized by Powder Metallurgy Technique

Abstract

In this investigation, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites. Commercial pure aluminium powder was used as matrix material and SiO2 coated ABOw was used as reinforcements. M icrostructures of the composites were characterized using scanning electron microscopy and high resolution scanning electron microscopy. Energy dispersive spectroscopy was employed to confirm the weight percentages of elements present in the composites. Transmission electron microscopic analysis was performed to observe morphological changes in the composites. X-ray diffraction analysis was carried out to confirm the phases of developed reinforcement and composites. A universal testing machine was employed for the observation of mechanical properties, viz. flexural strength, Young’s modulus and diametral compressive strength, and it was found that the mechanical strength improved by 50-55% in the case of 10 vol% SiO2 coated Al-ABOw composite. The effect of SiO2 coating on the hardness of fabricated composite was also evaluated and the maximum microhardness value was observed to be 46.2 HV in 10 vol% SiO2 coated composite. Themicrostructural analysis showed that excellent grain refined structures with improved mechanical strength were obtained.