ISSN: 0884-6804
CODEN: JCTRER
Page Count: 7

Fatigue-Life Behavior and Matrix Fatigue Crack Spacing in Unnotched SCS-6/Timetal®21S Metal Matrix Composites
Hillberry, BM
Research assistant and professor, Purdue University, School of Mechanical Engineering, IN

Herrmann, DJ
research associate, NASA Langley Research Center, VA

Ward, GT
Research assistant and professor, Purdue University, School of Mechanical Engineering, IN

Abstract

Fatigue tests of the SCS-6/Timetal®21S composite system were performed to characterize the fatigue behavior for unnotched specimens. The stress-life behavior of the unnotched [0/90]^2S laminates was investigated for stress ratios of R = 0.1 and R = 0.3. No difference in fatigue lives was observed when comparing the two stress ratios on a stress-range basis. The unnotched SCS-6/Timetal 21S composites had shorter fatigue lives than those reported in the literature for the SCS-6/Ti-15-3 composites; however, the neat Timetal 21S matrix material had a longer fatigue life than those reported for the neat Ti-15-3. Multiple matrix crack initiation sites were observed throughout the composite, as well as evenly spaced transverse fatigue cracks along the length of the specimens. The spacing between fatigue cracks was investigated, as were the effects of surface cracking on composite stiffness.

Keywords:
fatigue, titanium matrix, silicon-carbide fibers, unnotched, cross-ply laminates, matrix fatigue crack spacing

Paper ID: CTR10484J
DOI: 10.1520/CTR10484J
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