Correlation of tensile strength with fracture modes of KAOWOOL- and SAFFIL-reinforced 339 aluminum

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-1014-8· OSTI ID:335299

Baxter, W J; Sachdev, A K ^[1]

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1. General Motors R and D Center, Warren, MI (United States). Metallurgy Dept.

The tensile strengths of composites of 339 aluminum reinforced with either SAFFIL or KAOWOOL fibers are compared over the temperature range of 20 C to 300 C. For this type of composite, in which the discontinuous fibers are randomly oriented, the fibers perpendicular to the applied stress play a critical role, which in turn creates a dependence upon the interfacial bond strength. The KAOWOOL fibers form a strong interfacial bond so that tensile failure occurs either in the matrix at 300 C or by fiber cleavage at 20 C. In the T5 condition, the SAFFIL interface is weaker than the matrix alloy so that failure occurs by delamination of the transverse fibers. Thus, although the SAFFIL fibers are 40% stronger than the KAOWOOL fibers, the T5 composites have the same ultimate tensile strengths. A T6 heat treatment promotes an interfacial reaction with magnesium. This strengthens the SAFFIL interface so that failure occurs primarily in the matrix, producing higher composite strengths. The reaction with the KAOWOOL fibers is so extensive that the matrix, and therefore the composite strength, is drastically decreased. When account is taken of the different fracture modes, together with the matrix strengths as determined by nanoindentation, the calculated values of composite strength are in good agreement with experiment.

• Sponsoring Organization: USDOE
• OSTI ID: 335299
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 3 Vol. 40; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
ALUMINIUM OXIDES
COMPOSITE MATERIALS
FIBERS
FRACTOGRAPHY
FRACTURE PROPERTIES
SILICON OXIDES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TENSILE PROPERTIES