Centrifugally cast functionally graded materials: Fabrication and challenges for probable automotive cylinder liner application

In response to stringent environmental rules and rising public awareness, internal combustion (IC) engines have undergone fast improvement to reduce friction and wear in recent decades. Liner is a sacrificial engine component that protects and provides a smooth reciprocation surface to the engine block. High hardness aluminum alloys are used to produce cylinder liners. When reinforced with suitable ceramic particles, the strength, hardness, stiffness, thermal stability, and wear resistance of these alloys are improved. Here, the underlying challenges in liners are discussed, along with various solutions. The detailed fabrication process of centrifugally cast functionally graded composite materials (FGMs) for prospective use as liners is emphasized. Various parameters and their effect on mechanical and tribological properties are discussed in depth, and a comparison is made with existing Aluminum liners. A general framework for optimal material selection, parameter selection, and processing procedure is proposed to develop the FGM liner. In addition, challenges, research opportunities, and possibilities for the development of this field are presented.