Fatigue Crack Growth and Surface Reactions for Titanium Alloys Exposed to Water Vapor.
Abstract
Parallel fracture mechanics and surface chemistry studies have been carried out to develop understanding of environmentally assisted fatigue crack growth in titanium alloys. Room temperature crack growth response in water vapor was determined for annealed Ti-5A1-2.5Sn alloy and for Ti-6A1-4V alloy in the solution treated and solution treated plus over-aged conditions as a function of water vapor pressure from 0.266 to 665 Pa at a frequency of 5 Hz and a load ratio of 0.1. Reference data were obtained in vacuum. The kinetics of reactions of water vapor and oxygen with fresh surfaces of Ti-5A1-2.5Sn alloy were measured at room temperature. The results showed that the reactions with water vapor and with oxygen are both rapid; with an initial sticking coefficient of 1.0 for water vapor and of 0.54 to 0.84 for oxygen. The reaction with water vapor produced a monolayer of oxide (TiO), whereas 2 to 3 layers of TiO resulted from the reaction with oxygen.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1983
- Accession Number
- ADA127328
Entities
People
- G. W. Simmons
- Robert P. Wei
- S. J. Gao
Organizations
- Lehigh University