Enhanced laser direct joining of continuous carbon fiber reinforced polyetheretherketone and titanium alloy with controllable mechanical interlocks

To achieve high performance heterojunctions between continuous carbon fiber reinforced polyetheretherketone (CCF30/PEEK) and titanium alloy, a novel method of constructing strong micro-mechanical interlocks between two dissimilar materials was proposed and demonstrated through laser joining process. The influence of the laser joining conditions and the geometric characteristics of microcones on the joint performance was investigated. The interface morphologies were characterized to evaluate the quality of the formed mechanical interlocks at the joining interface. Shear tensile tests were conducted to evaluate the joint strength in different variables. Results revealed that wonderful micro-mechanical interlocks were successfully constructed between CCF30/PEEK and titanium alloy under the clamping pressure by using the optimal laser joining condition. Structure density of the fabricated microcones on titanium alloy surface is recognized as a crucial factor influencing the joint strength. And a maximum joint strength of over 52 MPa was achieved when the microcone density was 8.2 cones/mm². The proposed novel approach offers new insights for the construction of strong micro-mechanical interlocks between metal and plastic and the preparation of high performance heterojunctions.