Effects of argon ion irradiation on the microstructures and physical properties of carbon fibers

Eight kinds of carbon fibers with different microstructures have been exposed to argon ion implantation at 175 MeV – 1 μA for 399 min using AVF cyclotron, Takasaki Radiation Chemistry Research Establishment, JAERI. After ion irradiation changes in diameters and cross-sectional areas of carbon fibers were determined by scanning electron microscopy. Tensile properties were measured before and after ion irradiation. As a result, the diameter generally tended to decrease after ion irradiation, except for the carbon fiber with the dual microstructure that has two directions (radial and circumferential) of basal planes in the cross-section of the fiber. Tensile strength decreased after ion irradiation. The decrease in tensile strength suggests that changes in axial microstructures due to ion irradiation give an influence on the mechanical properties of the fibers.