Micromechanisms of Fatigue Crack Growth and Fracture Toughness in Metal Matrix Composites
Abstract
A detailed micromechanics analysis has been performed on a composite of 2014 aluminum alloy matrix with 15 vol.% particulate SiC. This composite was manufactured by the Dural Co. by casting and extrusion. The matrix alloy was peak aged before testing. The microstructure was found to contain about 3% intermetallic particles in addition to those expected for this material. Fatigue cracks were grown from approximately threshold to rapid fracture stress intensities. Fatigue cracks growth rates and fracture toughness were measured. Analyses of the crack tips were performed by stereoimaging at low and intermediate stress intensities, and just prior to the onset of rapid fracture. Detailed strain maps were derived, and considerable influence of SiC on strain was found. Analyses of microcracks near the main crack were made and found to have only a small influence on fracture. Key words: Metal matrix composites, Silicon carbide reinforcement, Fatigue crack growth, Fracture toughness, Particulate strengthening, Crack growth micromechanisms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1989
- Accession Number
- ADA203593
Entities
People
- D. L. Davidson
Organizations
- Southwest Research Institute