Fatigue crack growth of two advanced titanium alloys at room and elevated temperature

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:624251

Albertson, T P; Stephens, R R ^[1]; Bayha, T D ^[2]

---

1. Univ. of Idaho, Moscow, ID (United States)
2. Lockheed-Martin Aeronautical Systems Co., Marietta, GA (United States)

This paper provides fatigue crack growth information at low crack growth rates for two sheet titanium alloys: {beta}-21S, a {beta} alloy, and Ti-62222, and {alpha} + {beta} alloy. Room (25 C) and elevated temperature (175 C) fatigue crack growth tests at two different stress ratios, R = 01 and 0.5, were performed. Effects of temperature and stress ratio were evaluated in order to study the complex interaction between fatigue, environment, and loading conditions. Crack-opening load was measured throughout the test from automated compliance measurements and was used to adjust fatigue crack growth data for crack closure. For {beta}-21S, fatigue crack growth rates were similar at 175 and 25 C at a stress ratio of 0.2, while crack growth rates were lower at 175 versus 25 C at a stress ratio of 0.5 for the same nominal {Delta}K. Concepts associated with crack closure accounted for this as crack growth rates were found to be higher at 175 C than 25 C for both stress ratios when plotted as a function of {Delta}K{sub eff}, showing a temperature dependency on crack growth rate. For Ti-62222, fatigue crack growth rates were comparable between 25 and 175 C for R = 0.5, but were different at R = 0.1 where crack closure was observed at 175 C. Fatigue crack growth behavior of these two titanium alloys was comparable for all loading and temperature conditions.

• OSTI ID: 624251
• Report Number(s): CONF-950618--; ISBN 0-8031-2413-9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
FATIGUE
FRACTURE MECHANICS
MICROSTRUCTURE
STRESS ANALYSIS
TEMPERATURE DEPENDENCE
TITANIUM BASE ALLOYS