Enhanced tensile strength of titanium/polycarbonate joint connected by electron beam activated cross-weave carbon fiber cloth insert

Abstract

A new titanium (Ti)/polycarbonate (PC) joint [Ti/EBCF/PC] internally connected by homogeneous low potential electron beam irradiation (HLEBI) activated cross-weave carbon fiber (6 μm in diameter) cloth insert taking advantage of broad CF surface area had been developed. Applying HLEBI dose in the range of 0.043 to 0.43 MGy to the bare CF half-length prior to dipping in the thermoplastic PC molten resin enhanced ultimate tensile strength (σb) of Ti/EBCF/PC over that without HLEBI [Ti/CF/PC]. The 0.30 MGy dose appeared to be near the optimum resulting in σb of 20.7 MPa, an increase of 3.0, 3.9 and 21.1 times higher than that of Ti/CF/PC, with glue only [Ti/Glue/PC], and with spontaneous adhesion without glue [Ti/PC], at 7.00, 5.30, and 0.98 MPa, respectively. Moreover, regardless of HLEBI treatment, introduction of the CF insert into the joint prevented abrupt brittle fracture compared to the Ti/PC joint. The corrected ultimate tensile strength (cσb) defined as that of the 60 vol% CF-containing PC cross section portion calculated by rule of mixtures was also raised by the 0.30 MGy HLEBI to cσb = 195 MPa (Ti/EBCF/CFRPC); 6.89 and 31.7 times higher than that of Ti/CF/CFRPC and Ti/PC at 28.3 MPa and 6.16 MPa, respectively. The HLEBI probably enhanced the ability to adhere the CFs to difficult to adhere thermoplastic PC to generate the tremendously large friction force, with the aim of raising the safety level of lightweight material with high resistance to fracture for airplanes and automobiles.