EFFECT OF GRAPHITE PARTICLES ADDITION AND PROCESS PARAMETERS ON THE MECHANICAL PROPERTIES OF POLYETHYLENE/GRAPHITE SURFACE COMPOSITE FABRICATED BY FRICTION STIR PROCESSING

الملخص

Friction stir processing (FSP) is a novel solid state technique; it is employed for the improvement of the mechanical properties of a material and the production of surface layer composites instead of conventional processing technologies. This research aims to study the ability of applying Friction Stir Processing (FSP) on thermoplastic polymer in the form of high density polyethylene (HDPE) reinforcing by graphite particles with particle size of 25μm, filled in a groove of 1.5 mm depth on PE substrate. Friction stir process was carried out, using tool with scrolled shoulder to produce surface layer composite. The effect of processing parameters including rotational and transverse speeds on the mechanical properties of composite layer was studied. Wear test results showed a pronounced improvement in wear resistance of HDPE surface through reinforcement additions of graphite particles, where wear rate decreased by 70%, as compared with as received PE. The hardness of composite layer increased 18% higher than the as received material. OM revealed that high tool rotational speed resulted in homogeneous distribution of graphite particles and vice versa.