A novel method for measuring direct compressive properties of carbon fibres using a micro-mechanical compression tester

• Published in: Journal of materials science 1993-12, Vol.28 (24), p.6611-6616
• Main Authors: SHINOHARA, A. H, SATO, T, SAITO, F, TOMIOKA, T, ARAI, Y
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic and carbon fibers; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; Technical ceramics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF00356404

A novel method has been developed for measuring direct compressive properties such as strength and elasticity of a series of mesophase-pitch-based and PAN-based carbon fibers and approx10 mu m in diameter by uniaxial and transverse compression tests using a micro-mechanical tester. The fibers were shaped into cylindrical specimens, with their size ratio of length to diameter kept at about two to three, by separating them from a "thin film" made by polishing the cut faces of a strand of carbon fibers with epoxy resin as a matrix. Individual cylindrical specimens were stood up or laid down on a glass plate without any fixer for the measurements of axial and transverse compression properties of fibres, respectively. The fibers exhibited non-linear elasticity, with the compressive modulus decreasing with compressive deformation. The direct axial compressive strengths of pitch-based carbon fibers were found to be marginally lower than the indirect ones, whereas there was no significant difference between the two strength values for PAN-based fibers. The pitch-based fibers exhibited smaller average values of axial compressive strength than the PAN-based fibers. The transverse compressive strength, which decreases with an increase in elasticity of carbon fibers, exhibited a considerably lower average value than that of the axial compressive strength. Further, the axial compressive strength was found to be smaller than the direct tensile strength for the fibers.