Accession Number:

ADA171798

Title:

Investigation of Microstructural Factors that Cause Low Fracture Toughness in Silicon Carbide Whisker/Al Alloy Composites.

Descriptive Note:

Annual rept. 1 May 85-28 Feb 86,

Corporate Author:

VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE

Personal Author(s):

• Wawner,F. E.
• Harris,C. R.

Report Date:

1986-08-15

Pagination or Media Count:

38.0

Abstract:

The problem of low fracture toughness and low elongation to failure in silicon carbide whiskeraluminum alloy matrix composites is controlled by matrix composition and microstructure. Large, brittle, constituent particles as well as other precipitate phases along whisker interfaces strongly influence these properties. The purpose of this study is to define the fracture characteristics of the material from an atomic standpoint to define the factors that influence fracture toughness and elongation to propose a model for the failure mechanism and steps that can be taken to enhance the properties and to evaluate materials produced by using these concepts. Work during the first year of this program has emphasized microstructural and mechanical property evaluation of systems with altered chemistry of the alloy matrix and thermomechanical treatments of standard alloy systems.

Descriptors:

• *ALUMINUM ALLOYS
• *METAL MATRIX COMPOSITES
• *FRACTURE(MECHANICS)
• *SILICON CARBIDES
• *WHISKER COMPOSITES
• THERMOMECHANICS
• MECHANICAL PROPERTIES
• MICROSTRUCTURE
• FAILURE
• TOUGHNESS

Subject Categories:

• Laminates and Composite Materials
• Properties of Metals and Alloys
• Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE