High-temperature low-cycle fatigue and lifetime prediction of Ti-24Al-11Nb alloy

Journal Article · Mon May 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02670608· OSTI ID:72783

Malakondaiah, G; Nicholas, T ^[1]

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1. Wright Lab., Wright-Patterson AFB, OH (United States)

The influence of hold time on low-cycle fatigue (LCF) of Ti-24Al-11Nb was studied at 650 C. At 0.167 Hz, the alloy exhibits cyclic hardening at all strain levels studied and obeys the well known Manson-Coffin behavior. A 100-second hold at peak tensile or compressive strain at {+-}0.6 pct strain has no observable effect on cycles to failure. For hold times at {+-}0.5 pct strain, however, the fatigue lives are nearly halved and specimens show secondary cracking normal to the stress axis. The increase in inelastic strain as a result of hold time appears to be primarily responsible for the observed loss in fatigue life. A linear life fraction model, which considers both fatigue and creep damage, is found to provide good correlation of measured lives with predictions. For the range of test conditions employed, the total and the tensile hysteretic energy per unit volume, absorbed until fracture, remain nearly constant. The tensile hysteretic energy appears to be a more useful measure of fatigue damage for life prediction.

• Sponsoring Organization: USDOE
• OSTI ID: 72783
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 5 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
EXPERIMENTAL DATA
HEAT RESISTING ALLOYS
NIOBIUM ALLOYS
SERVICE LIFE
TEMPERATURE RANGE 0400-1000 K
THERMAL FATIGUE
TITANIUM BASE ALLOYS