Segregation to SiC/Al interfaces in Al based metal matrix composites

Strangwood, Martin; Hippsley, C. A.; Lewandowski, John J.

doi:10.1016/0956-716x(90)90418-g

Cited by 85 publications

(26 citation statements)

References 6 publications

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“…The segregation of Mg in the Al-Mg matrix composites has been widely studied. [8,[20][21][22][23][24] Mg can segregate at the grain boundaries, free surfaces, and interfaces of the Al matrix. There are two major types of segregations: equilibrium segregation and nonequilibrium segregation.…”

Section: B Segregation Of Mgmentioning

confidence: 99%

Synthesis, Tensile Testing, and Microstructural Characterization of Nanometric SiC Particulate-Reinforced Al 7075 Matrix Composites

Ahmed

Neely

Shankar

et al. 2010

Metall Mater Trans A

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This article examines the reasons for the poor performance of the nanometric scale SiC (n-SiC p ) particulate-reinforced Al 7075 composites. The composites having different volume fractions of the n-SiC p were synthesized via powder metallurgy (P/M) route and were uniaxially tested at room temperature. Experimental results showed a significant drop in the hardness and tensile properties of the composites in comparison with those of the monolithic Al. Microstructural analysis via scanning electron microscopy (SEM) revealed large segregation of Mg in the vicinity of the n-SiC p and at the grain boundaries of the Al matrix, which plausibly changed both the aging kinetics and tensile behavior of the Al matrix. The segregation of Mg increased with an increase in the volume fraction of the n-SiC p in the Al matrix. No Mg segregation was found in the monolithic Al. The clustering of the n-SiC p was observed from SEM with energy dispersive X-ray analysis. SEM also revealed cracks in the n-SiC p clusters and debonding between the clusters and Al matrix, which were considered as the main mode of fracture in the composites.

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Section: B Segregation Of Mgmentioning

confidence: 99%

Synthesis, Tensile Testing, and Microstructural Characterization of Nanometric SiC Particulate-Reinforced Al 7075 Matrix Composites

Ahmed

Neely

Shankar

et al. 2010

Metall Mater Trans A

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“…Solute segregation associated with interfaces may be present in the composite. [11] Dutta et al [12] and Suresh et al [13] have indicated that increasing the volume fraction of reinforcements will increase the dislocation densities in the matrix. The higher dislocation density in composites could also increase the solute diffusivity, and the enhanced diffusivity of Mg atoms has been suggested as the reason for the higher growth rate of precipitates in 6061-Al 2 O 3 composites.…”

Section: Heat Treatment Of the Brazed Jointsmentioning

confidence: 97%

Interfacial characteristics for brazing of aluminum matrix composites with Al-12Si filler metals

Weng

Chuang

1997

Metall Mater Trans A

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Discussions concerning the interfacial reactions and characterizations in brazing aluminum matrix composites are documented in this study. Joints of alumina particulate reinforced 6061 aluminum matrix composites were made using an Al-12 (wt pct) Si filler metal by vacuum brazing. The resulted maximum bonding strengths were 75.4, 81.5, and 71.8 MPa for 10, 15, and 20 vol pct alumina reinforcement, respectively. The microstructural examinations revealed that the bonding strength was strictly related to the reinforced alumina particles and the reaction products presented at the joint interfaces. During brazing, Mg segregated at the joining interface and alumina/6061 Al interface. Further, reactions between alumina and 6061 Al matrix resulted in the formation of Mg-rich phases, such as MgAl 2 O 4 and MgO, near the joining interface and the alumina reinforcement. The Si in the filler material penetrated into the metal matrix composites (MMCs) matrix and segregated at the alumina/6061 Al interfaces. This phenomenon can be confirmed by a joint between two alumina bulk specimens.

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“…The melting point of the interfacial region is expected to be reduced as a result of such segregation. 19 forced composites, and in the transverse and longitudinal directions of the whisker-reinforced composites. This result indicates that, despite the highly anisotropic nature of whiskers, compared with even irregular particulates, the rheological flow properties of these two types of materials are not much different.…”

Section: Interfacesmentioning

confidence: 99%

“…Most recently, Strangwood et a1. 19 have used a special finite-element modeling and scanning transmission electron microscopy technique to study solute segregation to SiC/ AI alloys interfaces. At the matrix/SiC interfaces in an underaged 2xxx/SiC/15p composite (where 2xxx contains 1.45 at.…”

Section: Interfacesmentioning

confidence: 99%

Superplasticity and superplastic forming of aluminum metal-matrix composites

Nieh

Wadsworth

1992

JOM

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Editor's Note: This article describes the composition of metal·matrix composites using a nomenclature system consisting of five parts: the matrix alloy designation, the reinforcement material, the volume percent of the reinforcement, the morphology of the reinforcement, and the generic temper designation. Under this system, a matrix of aluminum alloy 6061 reinforced with 40 vol. % SiC particulate and given a T6 heat treatment is written as 6061 /SiC/ 4Op-T6. When a matrix/reinforcement system is being discussed in general terms, it is deSignated in the same fashion, but a subscript is affixed to the reinforcement material designation to indicate whether it is whisker (w) or particulate (p). Thus, the family of composites formed by reinforcing aluminum alloy 2124 with Si,N. whiskers is designated 2124/Si,N«wl' Superplasticity hos been observed in many aluminum metal-matrix composites at extremely high strain rates (approximately 0.1-1 S-I). These materials generally exhibited a strain-rate sensitivity value of about 0.3 and a maximum elongation of about 300%. It is believed thot the presence ofa liquid phose, or in some cases a low-melting-point region, at the reinforcement/matrix interfaces is responsible for the phenomenon. This phenomenon is not observed in all reinforced composites, despite the fact thot they contain fine grain sizes. Thus, a fine matrix grain size is a necessary but insufficient condition for the high-strain-rate superplasticity.

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Segregation to SiC/Al interfaces in Al based metal matrix composites

Cited by 85 publications

References 6 publications

Synthesis, Tensile Testing, and Microstructural Characterization of Nanometric SiC Particulate-Reinforced Al 7075 Matrix Composites

Synthesis, Tensile Testing, and Microstructural Characterization of Nanometric SiC Particulate-Reinforced Al 7075 Matrix Composites

Interfacial characteristics for brazing of aluminum matrix composites with Al-12Si filler metals

Superplasticity and superplastic forming of aluminum metal-matrix composites

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