ISSN: 0884-6804
CODEN: JCTRER
Page Count: 10

Fatigue Behavior of a Cross-Ply Titanium Matrix Composite with Tensile and Zero Mean Load at Elevated Temperature
Boyum, EA
Professor and head, Department of Aeronautics and Astronautics and former graduate student, Air Force Institute of Technology, OH

Mall, S
Professor and head, Department of Aeronautics and Astronautics and former graduate student, Air Force Institute of Technology, OH

Abstract

The fatigue response of a cross-ply [0/90]^2S titanium (Ti-15-3) matrix composite reinforced with silicon carbide fibers (SCS-6) was investigated at 427°C. Tension-tension (tensile mean stress) and tension-compression (zero mean stress) loadings were applied. For the same stress range, tension-tension loading caused much lower fatigue lives and greater strain ratchetting than those under tension-compression loading. Despite the longer fatigue lives under tension-compression loading, additional plasticity sites and fatigue damage mechanisms were observed. Fatigue damage mechanisms could be classified into two distinct regimes, independent of mean load, fiber-dominated (fibers fracture prior to matrix cracking) at high-stresses and low-cyclic lives, and matrix dominated (matrix fatigue cracks prior to fiber fracture) at longer lives. Comparisons of the 427°C results are made with previously reported results at room temperature. Deformation mechanisms and fatigue lives were influenced by the testing temperature.

Keywords:
titanium matrix composites, fatigue, tension-tension, tension-compression, damage mechanisms

Paper ID: CTR10015J
DOI: 10.1520/CTR10015J
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