Thermomechanical fatigue life prediction in gas turbine superalloys: A fracture mechanics approach

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · AIAA Journal

OSTI ID:117660

Nissley, D M ^[1]

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1. United Technologies Corp., East Hartford, CT (United States)

A model is presented that was developed to predict thermomechanical fatigue crack initiation and estimate mode I crack growth of gas turbine hot section gas path superalloys. The model is based on a strain energy density fracture mechanics approach modified to account for thermal exposure and single crystal anisotropy. Thermomechanical fatigue crack initiation and small crack growth is modeled by employing an initial material defect size. Model capability was quantified by applying the model to two hot section gas path superalloys: uncoated MAR-M509 and MCrAlY overlay coated PWA 1480. Thermomechanical fatigue model stresses were obtained from nonlinear finite element analysis of thermomechanical fatigue specimen strain-temperature history. Nonlinear stress-strain behavior was predicted using unified viscoplastic constitutive models. Model thermomechanical fatigue life predictions were in good agreement with observed uniaxial thermomechanical fatigue specimen lives. Thermomechanical fatigue cracking effects captured by the model included coating thickness, single crystal anisotropy, cycle waveshape, dwell, and thermal exposure. 45 refs.

• OSTI ID: 117660
• Journal Information: AIAA Journal, Journal Name: AIAA Journal Journal Issue: 6 Vol. 33; ISSN AIAJAH; ISSN 0001-1452
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
FATIGUE
FINITE ELEMENT METHOD
FRACTURE MECHANICS
GAS TURBINES
HEAT RESISTING ALLOYS
MATHEMATICAL MODELS