MECHANISM OF FATIGUE DEFORMATION AT ELEVATED TEMPERATURES.
Abstract
The basic mechanism of fatigue is studied in annealed alpha-brass subjected to alternating torsion at room temperature, 100C, 200C, 300C, and 400C and in air. It is shown that the slip-zone microcracking which characterizes fatigue damage produced by small amplitudes at room temperature is progressively replaced by grain-boundary cracking at elevated temperatures, replacement being complete at 400C. Replacement occurs not because slip activity decreases but because slip-movements at elevated temperatures cease to concentrate in narrow zones and instead disperse. Decrease of amplitude at 400C though permitting longer lives of specimens before fracture actually causes increase in grain-boundary damage, an anomaly attributed to the greater difficulty at elevated temperature of starting and propagating a crack. Surface corrosion was most pronounced along slip-bands but since at elevated temperatures the slip bands showed no cracking, the surface corrosion did not appear to influence onset and early spread of fatigue damage. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1964
- Accession Number
- AD0607225
Entities
People
- M. Ronay
- W. A. Wood
- W. H. Reimann
Organizations
- Columbia University