Study on the fretting wear behaviour of AZ91/BLA MMCs and the implications that BLA has on that behaviour

Abstract

The core objective of this research is to develop an eco-friendly and cost-efficient engineering material termed “green composites.” These composites utilize waste bamboo leaf ash as a reinforcing element. Incorporating bamboo leaf ash into these composites offers several advantages due to its affordability, wide availability, and the presence of essential chemical compounds such as SiO2, CaO, TiO2, Al2O3, and others. Consequently, this investigation also examines the impact of bamboo leaf ash enriched with silica (referred to as BLA) on the fretting wear behaviour of Mg/BLA green composites. To create these composites, a bottom pouring stir casting setup was employed, with varying concentrations of BLA (1 wt% and 2 wt%) and reinforcement particles sized between 50 and 75 µm. The resulting cast products underwent machining in accordance with established testing standards and were subsequently polished using emery paper. These prepared samples were then subjected to testing in a fretting wear setup, utilizing a ball-on-flat contact configuration. The worn surfaces were thoroughly examined under a microscope, and data on the coefficient of friction were collected from the machine interface. The inclusion of BLA in the green composite enhanced the load-bearing capacity of the composite. Additionally, elements like CaO present in BLA acted as self-lubricating materials, resulting in a 21% reduction in the coefficient of friction and a 22% reduction in wear loss compared to the base alloy. The analysis of worn surfaces suggested that adhesive wear followed by oxidative and abrasive wear, were the predominant wear mechanisms in these green composites. Such environmentally-friendly materials with improved wear resistance properties have potential applications in situations prone to fretting wear.