Processing, microstructure, and mechanical behavior of cast magnesium metal matrix composites

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02671259· OSTI ID:116053

Luo, A ^[1]

---

1. Inst. of Magnesium Technology, Inc., Sainte-Foy, Quebec (Canada)

Magnesium metal matrix composites (MMCs) have been receiving attention in recent years as an attractive choice for aerospace and automotive applications because of their low density and superior specific properties. This article presents a liquid mixing and casting process that can be used to produce SiC particulate-reinforced magnesium metal matrix composites via conventional foundry processes. Microstructural features, such as SiC particle distribution, grain refinement, and particle/matrix interfacial reactions of the cast magnesium matrix composites, are investigated, and the effects of solidification-process parameters and matrix alloys (pure Mg and Mg-9 pct Al-1 pct Zn alloy AZ91) on the microstructure are established. The results of this work suggest that in the solidification processing of MMCs, it is important to optimize the process parameters both to avoid excessive interfacial reactions and simultaneously achieve wetting, so that a good particle distribution and interfacial bonding are obtained. The tensile properties, strain hardening, and fracture behavior of the AZ91/SiC composites are also studied and the results are compared with those of the unreinforced AZ91 alloy. The strengthening mechanisms for AZ91/SiC composite, based on the proposed SiC particle/matrix interaction during deformation, are used to explain the increased yield strength and elastic modulus of the composite over the magnesium matrix alloy. The low ductility found in the composites is due to the early appearance of localized damages, such as particle cracking, matrix cracking, and occasionally interface debonding, in the fracture process of the composite.

• Sponsoring Organization: USDOE
• OSTI ID: 116053
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 9 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CASTING
COMPOSITE MATERIALS
CRACKS
DUCTILITY
FRACTURE PROPERTIES
GRAIN SIZE
INTERFACES
MAGNESIUM ALLOYS
MAGNESIUM BASE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
PARTICULATES
SILICON CARBIDES
STRAIN HARDENING
TENSILE PROPERTIES
YIELD STRENGTH
YOUNG MODULUS
ZINC ALLOYS