Quantitative Microstructural Analysis of Unidirectional Carbon Fiber Reinforced Polymer Composites. Part 1. Microstructural Characterization of Composite Cross Section

Abstract : Individual axial tensile specimens of AS4/3501-6 and T300/934 unidirectional carbon fiber reinforced polymer composite laminate systems are characterized microstructurally. Fiber volume, fractional fiber volume, fiber uniformity, void volume, and variations in laminate thickness are acquired using automated quantitative image analysis (QIA). The sample preparation methods and QIA system procedures are fully explained. The problems in determining average or batch fiber contents in composite laminates using current methods are discussed. Possible problems in using micrometer thickness data in fiber content calculations are discussed when variations in specimen thickness due to surface contours are present. Variations in microstructure exhibited within a single fabricating company, between several fabricating companies, and between two different fiber-resin systems are demonstrated. Overall, QIA was determined to be a precise means of determining fiber and void contents and uniformity in individual test specimens prior to or after mechanical testing.