An Investigation on the Enhanced Wear Behavior of Ultrasonically Stirred Cast A356/SiO2np Nano-composites

Metal matrix nanocomposites (MMNCs) are becoming the materials of choice in a variety of engineering and medical applications owing to their exhibiting a superior combination of targeted properties. Amongst different MMNCs, aluminum-based composites are of special importance. In many applications, a relatively inferior wear property limits the use of this valued metal in practice. However, reinforcing aluminum and its alloys by ceramics, carbon allotropes, etc., may circumvent these limitations to a great extent. In the present study, aluminum alloy A356/SiO2 nanocomposite is fabricated by a vibration-assisted casting process, wherein varied amount of nanosilica, namely, 0.125, 0.25, and 0.375 wt.%, have been added to the melt. The use of power ultrasonic treatment had a great influence on the microstructure, hardness, and wear properties. Microstructural and XRD analyses were performed on the fabricated monolithic and composite samples. To evaluate wear behavior, a hardness test and pin-on-disk experiment were conducted on the samples under 60, 80, and 100 N forces at a constant speed of 1 m/s and the sliding distance was varied from 1000 to 2000 m. The abraded surfaces, wear debris, and EDS analysis were used to identify wear mechanisms. The samples having 0.125 wt.% exhibited the highest increase in hardness and the highest reduction in both friction coefficient and wear rate by 52%, 50%, and 68%, respectively. The main governing wear mechanism was abrasion, with limited evidence of delamination.

Automated summary

Metal matrix nanocomposites (MMNCs) are gaining popularity in engineering and medical applications for their superior properties, particularly aluminum-based composites. Reinforcing aluminum alloys with ceramics, carbon allotropes, etc., can significantly improve their wear resistance. In this study, an aluminum alloy A356/SiO2 nanocomposite was fabricated using a vibration-assisted casting process. The addition of 0.125 wt.% of nanosilica resulted in the highest increase in hardness and the greatest reduction in friction coefficient and wear rate by 52%, 50%, and 68%, respectively.