Investigation of the Failure Modes in a Metal Matrix Composite under Thermal Cycling
Abstract
There is currently wide interest in producing a vehicle capable of hypersonic flight. Structural materials in such a vehicle must be able to withstand high temperatures and retain high stiffness. Metal matrix composites (MMCs) are rapidly becoming the strongest candidates for these applications and concurrently, the need to study the effects of thermal cycling on them. This study emphasizes the development of a computer-controlled testing system that thermally fatigues a specimen under a variety of thermal conditions. A titanium matrix composite with silicon carbide fibers (SCS6/Ti-15-3) is the object of this study. To demonstrate the capability of this system, ten thermal fatigue tests were completed. The MMC was cycled from 300 F to 800 F while collecting strain and temperature data. A systematic study was undertaken to investigate the initiation and progression of the damage and its effect on mechanical properties as a function of applied thermal stresses. Results show that for up to 16,750 cycles, material properties remain unchanged and do not correlate with thermal cycling. Interior damage begins at 500 cycles as deformation of the fiber/matrix interface. Exterior damage begins at 1,500 cycles as delamination cracks along the ply seams. Theses. (aw)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA216195
Entities
People
- Paul G. Ermer
Organizations
- Air Force Institute of Technology