Effect of Reinforcement on the Pitting Behavior of Aluminum‐Base Metal Matrix Composites
01 Jun 1985-Journal of The Electrochemical Society (The Electrochemical Society)-Vol. 132, Iss: 6, pp 1277-1281
TL;DR: In this paper, the effect of graphite and silicon carbide reinforcements on the pitting behavior of a graphite/aluminum (Gr/Al) and SiC/Al matrix composites was examined.
Abstract: This paper examines the effect of graphite and silicon carbide reinforcements on the pitting behavior of graphite/aluminum (Gr/Al) and silicon carbide/aluminum (SiC/Al) metal matrix composites. Electrochemical corrosion tests were performed on both Gr/Al and SiC/Al composite specimens. Identical tests were completed on powder metallurgy processed aluminum and wrought aluminum of the same composition. The electrochemical behavio of the SiC/Al composites was essentially identical to that of the powder processed and wrought aluminum alloys; however, the pitting attack on the SiC/Al composites was distributed more uniformly across the surface, and the pits penetrated to significantly less depths. The presence of graphite in the Gr/Al composites did not cause an electropositive shift in corrosion potential as anticipated, but caused a substantial decrease in resistance to passive film breakdown. This effect is the predominant reason for the poor performance of Gr/Al composites in marine environments.
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02 Aug 1972TL;DR: In this article, important techniques to process metal matrix composites are described, then the interface region and its characteristics, properties of different metal matrix composite composites, and finally, the authors summarize different applications of metal matrices composites.
Abstract: Metal matrix composites consist of a metal or an alloy as the continuous matrix and a reinforcement that can be particle, short fiber or whisker, or continuous fiber. In this chapter, we first describe important techniques to process metal matrix composites, then we describe the interface region and its characteristics, properties of different metal matrix composites, and finally, we summarize different applications of metal matrix composites.
264 citations
TL;DR: In this paper, the corrosion of metal matrix composites (MMCs) is reviewed with emphasis on relating MMC corrosion behaviour to the electrochemical and chemical properties of MMC constituents.
Abstract: The corrosion of metal matrix composites (MMCs) is reviewed with emphasis on relating MMC corrosion behaviour to the electrochemical and chemical properties of MMC constituents. Galvanic corrosion between the reinforcement constituent and the metal matrix governs the corrosion behaviour of many MMCs. Other factors such as residual contaminants of MMC processing and the formation of interphases between reinforcement and matrix can also have pronounced effects on MMC corrosion behaviour. The lack of inherent resistance to corrosion of some MMCs requires that they be coated with organic or inorganic coatings for protection. Although the ultimate goal is to engineer and design MMCs to have good inherent resistance to corrosion (while maintaining excellent mechanical properties), no significant breakthroughs have been achieved in this area for MMCs that are typically prone to corrosion (e.g. graphite-aluminium MMCs). In this review, aluminium, magnesium, lead, depleted uranium, and stainless steel MMCs...
164 citations
TL;DR: In this article, a review of the literature relating to aluminum matrix composites reinforced by ceramic particles, short fibers or whiskers is presented with respect to their nature, morphology and mechanical behavior.
Abstract: This article reviews the literature relating to aluminum matrix composites reinforced by ceramic particles, short fibers or whiskers. The main reinforcements which have been used are presented with respect to their nature, morphology and mechanical behavior. The influence of matrix alloying elements on ceramic-metal compatibility is discussed. Most fabrication techniques which have been proposed are described and particular attention is paid to the methods suitable for large scale production. The mechanical characteristics of this kind of composite are reported and compared in relation to processing parameters. Finally, models giving a rough prediction of the mechanical behavior of the composites are discussed.
150 citations
TL;DR: In this article, the effect of the size and volume fraction of SiC particulates on the microstructural and corrosion behavior of Al/SiC metal matrix composites (MMCs) was studied.
Abstract: Several Al/SiC MMCs having several volume fractions up to 15 vol.% and different SiC particulates average sizes, typically, 11, 6 and 3 μm were fabricated using conventional powder metallurgy (PM) route. The effect of the size and volume fraction of SiC particulates on the microstructural and corrosion behavior of Al/SiC metal matrix composites (MMCs) were studied. The results revealed that the Al/SiC MMCs exhibited higher density than pure Al matrix. The static immersion corrosion tests of Al/SiC MMCs in 3.5 wt.% NaCl aqueous solution at several temperatures showed that, at ambient temperature, the Al/SiC MMCs have better corrosion resistance than the pure Al matrix. Reducing the SiC particles size and/or increasing the volume fraction of the SiC particulates reduce(s) the corrosion rate of the Al/SiC MMCs. In contrast, the Al/SiC composites exhibited higher corrosion rates at 50 °C and 75 °C than the pure Al matrix.
148 citations
TL;DR: In this paper, the pitting susceptibility of metal matrix composites based on aluminium (1050) reinforced with particulate silicon carbide has been examined using polarization in neutral 1N NaCl solution at 25 °C.
Abstract: The pitting susceptibility of metal matrix composites based on aluminium (1050) reinforced with particulate silicon carbide has been examined using polarization in neutral 1N NaCl solution at 25 °C. Various tests have been carried out to assess the effects of reinforcement particle size, particle volume fraction, internal stresses, reaction product at the particle/matrix interface and voids at the interface. It has been found that the MMCs show increased susceptibility to pitting attack compared with unreinforced alloys and that the major contribution to this enhanced attack arises from voids at the reinforcement/matrix interface. The voids may arise either as a result of poor bonding at the reinforcement/matrix interface or from the presence of cracked reinforcement particles.
145 citations