Accession Number:

ADA243894

Title:

Tensile Strength Characterization of a Metal Matrix Composite with Circular Holes

Descriptive Note:

Master's thesis,

Corporate Author:

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

Personal Author(s):

Report Date:

1991-12-01

Pagination or Media Count:

146.0

Abstract:

Static tensile testing conducted at room temperature and 650 C shows notch sensitivity for a quasi-isotropic lay-up of a titanium alloy metal matrix composite. The specific material used was SCS-6Beta 21S. Some unnotched specimens were tested and then the diameter-to-width ratio was varied from 0.1 to 0.4. The room temperature unnotched strength is 840 MPa, and the strength falls to less than half this value at 650 C. The off-axis plies of the 0, or - 45, 90s lay-up exhibit debonding of the fibers from the matrix at only ten percent of failure stress. This debonding is shown with acetate replicas and acoustic emission. By modeling the debonded plies with the Halpin-Tsai equations, a modulus is calculated for the debonded material which correlates very well with the experimental modulus. A fiber dominated failure exists at both temperatures, but the fiber pullout exists only at 650 C. Etching away the matrix from the 0 fibers showed a small area near the hole where fibers were damaged. The size of this damage zone correlated very well with the critical distance for the Whitney-Nuismer Point Stress failure prediction method.

Subject Categories:

  • Laminates and Composite Materials
  • Metallurgy and Metallography
  • Test Facilities, Equipment and Methods
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE