Accession Number:

ADA169839

Title:

Micromechanisms of Crack Growth and Fracture Toughness in Metal Matrix Composites.

Descriptive Note:

Technical rept. 29 Apr 85-29,

Corporate Author:

SOUTHWEST RESEARCH INST SAN ANTONIO TX

Report Date:

1986-06-01

Pagination or Media Count:

47.0

Abstract:

Subcritical crack growth and rapid fracture of the mechanically alloyed aluminum alloy IN-9052 reinforced with SiC particles have been investigated. Fatigue crack growth rates for the composite exceed those of the unreinforced alloy, except that the threshold stress intensity for growth is higher for the composite. Fracture toughness of the composite is about 9 square root of M cubed compared to a reported value of 29 square root of M cubed for the unreinforced alloy. The contributions to fracture toughness from work done within the plastic zone and in formation of the void sheet have been computed using analytical models. Fracture toughness is shown to result almost entirely from work done within the plastic zone of the growing crack. The matrix microstructure and the particulate characteristics are found to account for the elastic and fracture properties of this composite.

Subject Categories:

  • Laminates and Composite Materials
  • Properties of Metals and Alloys
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE