High fracture resistance of carbon fiber treated by electron beam irradiation

Abstract

A crack reduction by electron beam (EB) irradiation treatment for carbon fiber, used without the traditional method of accompanying heat, was developed to modify the mechanical properties at lower temperature. The EB treatment improved the resistance to fracture. Namely, the maximum ratio of fractured samples (maxRf) and the minimum bending strain on fracture (minεf) were defined as simple indicators of fracture resistance and became smaller by the EB treatment. Furthermore, a critical density of dangling bonds for a fracture was suggested and determined for carbon fiber treated by EB irradiation. The EB irradiation to reduce cracking and the determination of the critical density of dangling bonds are new concepts that can be broadly applied in the fields of aerospace and rapid-transit production engineering.

Improved Strength in Carbon Fiber Reinforced Plastics due after Electron Beam Irradiation

“…Bending fracture strain 3) and the tensile fracture stress 4) of fine carbon fiber have been obtained in our previous work. EB irradiation generally enhanced the bending fracture strain 3) and the tensile fracture stress.…”

“…Bending fracture strain 3) and the tensile fracture stress 4) of fine carbon fiber have been obtained in our previous work. EB irradiation generally enhanced the bending fracture strain 3) and the tensile fracture stress. 4) The strengthening of carbon fiber is assumed to be based on the annihilation of vacant sites with dangling carbon bonds in graphite hexagonal atom structure.…”

“…The sheets were homogeneously irradiated using an electron-curtain processor (Type CB175/15/180L, Iwasaki Electric Co. Ltd. Tokyo). [3][4][5][6][7][8][9][10] A tungsten filament in a vacuum generated the sheet beam. The acceleration voltage and the current density were 170 kV and 4.0 mA, respectively.…”

“…In recent publications we report that electron beam (EB) irradiation enhances the bending fracture strain 3) and the tensile fracture stress of carbon fiber. 4) However, the influences of EB irradiation on the mechanical properties of CFRP have not hitherto been studied.…”

Effects of Electron Beam Irradiation on Charpy Impact Value of GFRP

“…Although influences of high energy electron beam irradiation on the fracture toughness of FRP have been reported, 3) no one has succeeded the strengthening of carbon fiber reinforced polymer (CFRP). On the other hand, low energy sheet electron beam (EB) irradiation often induces hardening, high wear resistance and sterilization, [4][5][6][7] In addition, the irradiation has improved not only the bending fracture strain of carbon fiber, 8) but also the deformation resistivity, strength and fracture strain during static tensile testing. 9) Our recent publication has succeeded in showing that the EB-irradiation with low energy enhances the fracture stress during static bending testing, 10) tensile strength 11) and the dynamic fracture toughness evaluated by impact value 12) for CFRP.…”