Accession Number:

ADA291479

Title:

Investigation of Tension-Compression Fatigue Behavior of a Notched Cross-Ply Metal Matrix Composite at Elevated Temperature.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1994-12-01

Pagination or Media Count:

148.0

Abstract:

This research extends the existing knowledge of MMC fatigue damage mechanisms by studying the tension-compression fatigue behavior of a notched cross-ply laminate MMC at elevated temperature. A 09025 SCS-6Ti-15-3 laminate with a center hole was subjected to tension-compression fatigue at 427 deg C 800 deg F. Stress and strain data was taken to evaluate macro-mechanic behavior of the material. Microscopy and fractography were performed to characterize the damage on a micro-mechanical level. Crack initiation and progression was monitored using acetate face replicas. Four cracks were found to develop around the periphery of the hole, two of which became dominant and proceeded through to the end of the specimen. On a maximum applied stress basis, tension-compression notched specimens had shorter fatigue lives than tension-tension notched specimens. Also, tension-compression adds more damage due to the compressive portion of the loading, and tension-compression loading increased the time to crack initiation for a given maximum stress and increased the rate of crack propagation over tension-tension cases. MM

Subject Categories:

  • Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE