SEDL / STP / STP1080-EB / STP25401S

Mechanical Characterization of Unnotched SCS⁶/Ti-15-3 Metal Matrix Composites at Room Temperature

Johnson, WS
Senior research engineer, NASA Langly Research Center, Hampton, VA

Lubowinski, SJ
Engineer, BASF Corporation, Charlotte, NC

Highsmith, AL
Assistant professor, Texas A&M University, College Station, TX

Pages: 26    Published: Jan 1990

Download this paper for $25 PDF (628K)          View License Agreement
Abstract

The Ti-15-3 metal matrix composites containing silicon carbide (SCS⁶) fibers, in five different lay-ups, have been tested at room temperature to determine static strengths and mechanical properties. Experimental data and predicted values of the laminate properties and strengths showed good correlation. The off-axis laminate plies (that is 90° and 45°) suffered fiber/matrix interface failures at stress levels as low as 20 ksi, thus significantly affecting the mechanical properties of the laminate. Edge replicas were used to verify the fiber/matrix separations. Microscopic examinations determined that the fiber/matrix failures were occurring in the titanium/silicon reaction layer. Fatigue tests were performed on unnotched specimens to determine the number of cycles to failure versus cyclic stress level. It was found that the stress in the 0° fiber could be used to correlate the fatigue life of different laminates containing 0° phes.