Investigation of tension-compression fatigue behavior of a cross-ply metal matrix composite at room and elevated temperatures. Master's thesis

Technical Report · Wed Dec 01 04:00:00 EST 1993

OSTI ID:5438067

Boyum, E A

This research, the first load-controlled tension-compression fatigue testing to be performed on a MMC, extends the existing knowledge of MMC fatigue damage mechanisms to include the tension compression loading condition. To accomplish this, a (0/90)2, SCS-6/Ti-15-3 laminate was subjected to tension-tension fatigue at room temperature, and tension-compression fatigue at both room temperature and 427 deg C. Stress and strain data was taken to evaluate the macro-mechanic behavior of the material. Microscopy and fractography were performed to characterize the damage on a micro-mechanic level. On a maximum applied stress basis, the room temperature tension-tension specimens had longer fatigue lives than the room temperature tension-compression specimens. The room and high temperature tension-compression fatigue lives were nearly identical in the fiber-dominated high stress region of the SN curve. However, the increased ductility and diffused plasticity of the titanium matrix at 427 deg C delayed the onset and severity of matrix cracking, and thus increased the elevated temperature fatigue lives in the matrix dominated region of the SN curve. In all cases, matrix damage initiated at reaction zone cracks which nucleated both matrix plasticity and matrix cracking. Metal matrix composite, Elevated temperature, Fatigue testing, Compression, Fully-reversed, Titanium, Silicon carbide.

• Research Organization: Air Force Inst. of Tech., Wright-Patterson AFB, OH (United States). School of Engineering
• OSTI ID: 5438067
• Report Number(s): AD-A-273731/0/XAB; AFIT/GAE/ENY--93D-6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALLOYS
CARBIDES
CARBON COMPOUNDS
COMPOSITE MATERIALS
COMPRESSION
FATIGUE
MATERIALS
MATRIX MATERIALS
MECHANICAL PROPERTIES
SILICON CARBIDES
SILICON COMPOUNDS
STATIC LOADS
STRESS ANALYSIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TENSILE PROPERTIES
TITANIUM ALLOYS
TITANIUM BASE ALLOYS