Micromechanisms of Fatigue Crack Growth and Fracture Toughness in Metal Matrix Composites
Abstract
Research objectives under which this work was initiated were as follows: 'To understand the mechanisms of subcritical crack extension and fracture toughness in particulate-reinforced metal matrix composites projected for Naval applications in which one or more of these parameters control service. ' The factors thought to be important in 1985 were the processing variables by which these materials were fabricated and the role of SiC particles in altering fatigue crack growth and fracture toughness of the matrix alloys. The methods used in reaching for these objectives include the techniques of experimental micromechanics. Experiments in fatigue crack growth and fast fracture were conducted for a variety of composites obtained from different manufacturers, and these materials were thoroughly characterized. Materials characterized were picked in order to: (1) determine the effects of differences in matrix composition and heat treatment, (2) determine the effect of SiC volume fraction, and (3) account for differences in particle size. Materials were obtained from two different manufacturers. IN-9051+15v/o SiC (essentially Al-4Mg) and IN- 9021+15v/o SiC, both made by mechanically alloying and powder metallurgy were obtained from Novamet. The remainder of the composites made by ingot metallurgy by Dural Aluminum Composites Co., were: Al-4Mg+15v/o SiC, 2014+15v/o SiC, 2014+25v/o SiC, 2024+15v/o, 2014+15v/o SiC, and 7475+15v/o SiC. Keywords: Metal matrix composites, Silicon carbide, Reinforcement, Fatigue crack growth, Fracture toughness, Particulate strengthening, Crack growth micromechanics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 28, 1990
- Accession Number
- ADA223863
Entities
People
- David L. Davidson
Organizations
- Southwest Research Institute