Wettability in Metal Matrix Composites

Abstract

Metal matrix composites (MMCs) have been developed in response to the enormous demand for special industrial materials and structures for automotive and aerospace applications, wherein both high-strength and light weight are simultaneously required. The most common, inexpensive route to fabricate MMCs or metal matrix nanocomposites (MMNCs) is based on casting, wherein reinforcements like nanoceramics, -carbides, -nitrides, elements or carbon allotropes are added to molten metal matrices; however, most of the mentioned reinforcements, especially those with nanosized reinforcing particles, have usually poor wettability with serious drawbacks like particle agglomerations and therefore diminished mechanical strength is almost always expected. Many research efforts have been made to enhance the affinity between the mating surfaces. The aim in this paper is to critically review and comprehensively discuss those approaches/routes commonly employed to boost wetting conditions at reinforcement-matrix interfaces. Particular attention is paid to aluminum matrix composites owing to the interest in lightweight materials and the need to enhance the mechanical properties like strength, wear, or creep resistance. It is believed that effective treatment(s) may enormously affect the wetting and interfacial strength.

Investigating the Microstructural and Mechanical Properties of Novel Ternary Reinforced AA7075 Hybrid Metal Matrix Composite

“…Further, mixing reinforcements in the molten matrix at elevated temperatures increases the probability of oxide formation [ 18 ]. The factors that contribute to the increased porosity in MMCs and HMMCs include wettability issues [ 60 ], the temperature gradient between the matrix and reinforcement, non-uniform distribution of reinforcement particles in the matrix, the particle size of reinforcements, stirring speed, stirring time, and the pouring rate of the molten mixture into the mold [ 25 , 61 , 62 , 63 , 64 , 65 ].…”

Wetting of MXenes and Beyond

“…1 Young’s model of wetting with three vectors of solid–gas, solid–liquid, and liquid–vapor surface tensions, reprinted from Ref. [ 9 ] Based on Eq. ( 1 ), raising the solid–liquid interfacial energy, increasing solid surface energy, and reducing liquid surface tension, all diminish the contact angle in solid–liquid interface being vital for better wettability.…”

“…In these applications, a reinforcing agent should be properly wetted by a given host material leading to a desired physical integrity; however, most of the common nanomaterials usually have a hydrophobic surface making them hard to be easily dispersed in a variety of matrices of polymers, metals, ceramics, etc. [ 9 ]. Further, owing to great contact angles of these poorly dispersed nanomaterials, the bonding strength in the interfacial zone tends to diminish when the given nanomaterial is embedded in a hybrid/composite system.…”

“…Similar phenomenon has also been reported in polymer composites as the particles tend to agglomerate due to interparticle forces such as van der Waals. According to the literature, such poor wetting and inadequate surface hydrophilicity has been a great bottleneck in nanocomposites; extensive research efforts have been made to date to address the mentioned challenge; strategies such as the coating of nanomaterials, thermal methods [ 10 ], or additionally mechanical treatments have been developed to fight against the inherent hydrophobic nature of the common nanomaterials, all trying to boost the nanomaterial matrix affinity [ 9 , 11 – 13 ].…”

Numerical Simulation on Thermal Stresses and Solidification Microstructure for Making Fiber-Reinforced Aluminum Matrix Composites

“…The interface problem has been a core issue in manufacturing metal matrix composites, especially for active metals such as aluminum [12][13][14][15]. High infiltration temperature is a key factor in preparing carbon and aluminum (C/Al) composites.…”