Accession Number:

ADA230388

Title:

Investigation of Fatigue Damage Mechanisms in a Metal Matrix Composite Under Elevated Temperature

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1990-12-01

Pagination or Media Count:

115.0

Abstract:

This study investigated the fatigue damage initiation and progression in SCS-6Ti-15-3 under an environment of fatigue loading at isothermal temperature. This program included two parts. First, an 808 Ultimate Tensile Strength system was set up to accommodate testing at two frequencies of 2.0 and 0.0208 cps at a constant temperature of 427 deg C. Second, at intervals during the load cycle process, the test specimens were characterized by establishing damage parameters based on changing modulus of elasticity, average strain, strain range, and ultimate tensile strength. Damage progression was documented in the form of failure of the fiber-matrix interface, matrix cracking, fiber breaking, and debonding of the fibers. Crack initiation locations and growth patterns were peculiar to specific test conditions of frequency and stress level. Also, analysis of the fatigued specimens and test data revealed matrix failure mechanisms ranging from ductile failure to cleavage fracture. The results of this study clearly show that temperature, frequency as well as stress levels are important design considerations for this composite in fatigue loading applications.

Subject Categories:

  • Laminates and Composite Materials
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE