SYMPOSIA PAPER Published: 01 January 1996

A Hot-Spot Thermal Fatigue Test of a Titanium Matrix Composite


A thermal fatigue test was designed and executed based on heating and cooling of a local spot in a thin titanium matrix composite (TMC) sheet by quartz lamps. This approach offers two features not offered by the load-controlled testing of standard coupons: (1) the stress state is biaxial instead of uniaxial, and (2) the mean stress is primarly compressive instead of tensile. A test rig was constructed to subject a small spot in the center of a 51-by 51-mm sheet of TMC to alternate heating and cooling between room temperature (RT) and 615°C. A specimen of unidirectionally reinforced SCS-6/Ti-6-2-4-2 was subjected to cycling with intermittent inspection for damage. Minimal cracking was observed in this test even after 10 000 cycles. Load-controlled low cyclic fatigue (LCF) and thermomechanical fatigue (TMF) tests were also performed on this material. The observed life in the hot-spot test was significantly greater than uniaxial transverse tensile fatigue load-controlled data would suggest based on a thermal stress analysis of the test panel. However, it was in reasonably good agreement with longitudinal, uniaxial load-controlled out-of-phase TMF data.

Author Information

Wright, PK
GE-Aircraft Engines, Cincinnati, OH
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Developed by Committee: D30
Pages: 480–493
DOI: 10.1520/STP18237S
ISBN-EB: 978-0-8031-5320-2
ISBN-13: 978-0-8031-2039-6