ISSN: 0884-6804
CODEN: JCTRER
Page Count: 4

Screening of Metal Matrix Composites Using Ultrasonic C-Scans
Johnson, WS
Senior research engineer, NASA Langley Research Center, VA

Abstract

This paper will show how ultrasonic C-scans can be used to find some types of defects in continuous fiber reinforced metal matrix composites such as boron/aluminum composites. These defects will then be related to the fatigue behavior and fracture location of each inspected specimen. The C-scan technique was used to determine the relative amount of defects in boron/aluminum composites. The defects were primarily identified as gaps in the fiber spacing. Those specimens with higher defect densities had shorter fatigue lives, lower fatigue endurance limits, and greater reductions in the elastic unloading modulus (that is, stiffness) because of fatigue cycling. This type of data could be used to set accept/reject levels for a composite panel based on C-scan indications.

Keywords:
metal matrix composites, nondestructive inspection, fatigue, defects, boron fibers, aluminum matrix, stiffness

Paper ID: CTR10146J
DOI: 10.1520/CTR10146J
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