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Top1. Introduction
Low density and high performance of aluminium matrix composites (AMCs) make it a potential candidate for automobile, aerospace, and other manufacturing industries. The current state of the art of AMC manufacturing consists of in-situ synthesis, which holds many advantages over other techniques such as stir casting, powder metallurgy, and spray forming. In-situ synthesis of AMCs is advantageous for the generation of fine thermally stable reinforcement particles and process flexibility (Pramod, et al. 2015; Chakraborty et al., 2012). Recently, an ultrasound-assisted in-situ casting technique (UST) has been developed for the synthesis of AMCs, which can refine the particle size down to submicron and nano regime and also enhance the uniform dispersion of reinforcement particles. A wield of UST towards the in-situ composite synthesis is beneficial for tailoring the size and distribution of reinforcement particles and thus enhance the mechanical properties of AMCs (Meti et al., 2017). Recent studies including the works by the current author’s reports that the ultrasonic-assisted composite fabrication can synthesize a good quality Al/TiB2 composite with TiB2 particles of micron, submicron and nanometer in size with enhanced mechanical properties (Siddhalingeshwar et al., 2009; 2011a, 2011b; 2013, Patil et al., 2020; Banapurmath et al., 2020).
Along with the microstructural and mechanical properties, the tribological characteristics of AMCs are also a significant design element. The tribological behavior of AMCs dramatically depends on the size and volume fraction of reinforcement particles. A better understanding of the mechanism of wear and the parameters affecting the wear can give the insight to design a new material with improved wear resistance. The dry sliding wear of composite materials involves complex processes like mechanical, chemical, and thermal interactions between the two sliding surfaces. Delamination is one of the primary phenomena that causes a drastic alteration in the dry sliding wear rate. Literature summarizes that the size, volume fraction, and dispersion of reinforcement particles can affect the delamination phenomena. Hence, the studies on dry sliding wear of composites, delamination pattern, and the role of parameters like reinforcement particle size, the fraction of particles, and its dispersion are of great significance for the design of a wear-resistant composite. The tribological behavior of AMCs reinforced with a various fraction of both ex-situ and in-situ reinforcements such as SiC, TiC, B4C, TiB2, graphite, and fly ash are available in the literature. The studies on the influence of particle size and dispersion of particles on the wear performance of submicron and nano-size particle reinforced composites are minimal.