The influence of carbon fiber orientation on the mechanical and tribological behavior of carbon fiber/LCP composites

Focus of this study has placed on the influences of carbon fiber orientation and weight percentage on the mechanical and tribological behavior of carbon fiber/LCP (liquid crystal polymer) composites prepared through injection molding. The experimental results showed that the mechanical properties and the frictional behavior of the carbon fiber/LCP composites were much better and more stable than those of pure LCP. If the testing direction is parallel to the fiber axis in the composite, then the longitudinal fiber would afford a higher strength and better wear resistance to the applied load. Besides, P-type composites (sliding direction parallel to the fiber orientation) appear to have much better Young's modulus and tribological properties. Nevertheless, as the weight percentage of carbon fibers increases, more random fiber orientation and more debonding area would cause the tensile strength and the tribological performance of the specimen not so favoring. On the other hand, if fibers axes in specimens are perpendicular to the sliding direction, more cracks, more cut fibers and debonded areas, and deeper grooves would be found on the rougher surface by ploughing and fretting. In comparison with both AP (sliding direction perpendicular to the fiber orientation) and P types specimens, a higher weight loss would result for the AP type specimen than that of the P-type specimen.