Environmental Effects on Fatigue Crack Initiation.
Abstract
Models of microscopic failure mechanisms important to the crack initiation stage of the fatigue failure of aluminum alloys have been proposed and verified. Included are: (1) a model relating rate of nucleation of surface microcracks at intermetallic particles to particle and grain size and ambient humidity; (2) and models which relate rate of growth of surface microcracks, with lengths of approximately the grain size, to the alloy microstructure in the region of a nucleation site and to ambient humidity. The models have been used to develop a Monte Carlo simulation of the fatigue failure of aluminum alloys which can be used to predict the effect of alloy microstructure and environmental humidity on: (1) mean and scatter in fatigue lifetime; (2) microscopic parameters such as numbers and lengths of microcracks, and microcrack closure stresses. Simulated and measured fatigue behavior are compared for several aluminum alloys. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1979
- Accession Number
- ADA064443
Entities
People
- O. Buck
- W. L. Morris