AN OVERVIEW OF SELF-LUBRICATED ALUMINUM-BASED HYBRID COMPOSITES, PART A: SOLID LUBRICANTS AND PROCESSING ROUTE

Innovation in solid lubricant technology deserves the attention of design engineers for multiple applications, not only in normal environments but also in unfavorable ones. Self-lubricating composites belong to a class of materials that provide a thin layer of lubricant, known as tribofilm, when two surfaces rub against each other. This type of composite has different chemistry, microstructure, and crystal structure on the wear surface as compared to unreinforced solid lubricant metal matrix composites, thanks to the presence of solid lubricants. However, these lubricants, which offer extremely low friction and a long lifetime, do not respond appropriately to different environmental conditions. Therefore, strategies have been developed to construct novel aluminum-based self-lubricating hybrid composites that can adapt to various environmental conditions. This article explores the potential of solid lubricants as essential components in self-lubricating hybrid composites. The present review focuses on Al-based self-lubricating hybrid composites and highlights the types of solid lubricants used as reinforcing phases and several processing methods adopted to fabricate different aluminum-based hybrid composites.