Sr effect on the microstructure and tensile properties of A357 aluminum alloy and Al(2)O(3)/SiC-A357 cast composites

The effect of strontium as a modifier on the microstructures and tensile properties of two castable particulate metal matrix composites has been studied. The particulate metal matrix composites had similar matrix alloy (A357) but different reinforcing fine particles (silicon carbide and alumina). Re...

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Bibliographic Details
Published in:Materials characterization 2009-11, Vol.60 (11), p.1361-1369
Main Authors: Razaghian, A, Emamy, M, Najimi, A A, Ebrahimi, S.H.S.
Format: Article
Language:English
Subjects:
ALUMINIUM ALLOYS
ALUMINIUM OXIDES
ELONGATION
EUTECTICS
INTERFACES
INTERMETALLIC COMPOUNDS
MATERIALS SCIENCE
MATRIX MATERIALS
MICROSTRUCTURE
PARTICLES
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SILICON ALLOYS
SILICON CARBIDES
STRONTIUM
TENSILE PROPERTIES
X-RAY SPECTROSCOPY
YIELD STRENGTH
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Summary:The effect of strontium as a modifier on the microstructures and tensile properties of two castable particulate metal matrix composites has been studied. The particulate metal matrix composites had similar matrix alloy (A357) but different reinforcing fine particles (silicon carbide and alumina). Results showed that the addition of 0.03% strontium makes a modest improvement to the yield strength, ultimate tensile strength and elongation percentage values, and the scatter of these properties, but makes a significant improvement to minimum strength and elongation results. Microstructural examinations by scanning electron microscope and energy dispersive spectroscopy analysis of metal matrix composites showed segregation of strontium on both the silicon carbide and alumina particles. Further results showed that the addition of higher strontium levels contributes to the over-modification of the eutectic silicon and promotes the formation of an Al-Si-Sr intermetallic compound on the particle /matrix interface.
ISSN:1044-5803
1873-4189
DOI:10.1016/j.matchar.2009.06.008