MECHANICAL AND TRIBOLOGICAL PERFORMANCE OF Al-x SiC COMPOSITES PRODUCED BY POWDER METALLURGY TECHNIQUE FOR THROTTLE VALVES APPLICATIONS

The present work aims to study the effect of SiC particles addition on themicrostructural, mechanical, and tribological properties of Al/SiC compositesproduced by hot compaction powder metallurgy technique. High-energy planetaryball milling was used for mixing the pure Al powder with different SiC particlescontent of 2.5, 5, 7.5, and 10 wt.% at a speed of 350 rpm for 12 h. A hot compactiontechnique was used to produce the present Al/SiC composites at a pressure andtemperature of 900 MPa and 550 ºC, respectively. Theoretical, actual, and relativedensities as well as porosity percentages were measured. Scanning electron microscopy(SEM) was used to study the microstructural observations of present composites.Mechanical properties tests, which include microhardness and compression tests, wereconducted at room temperature to estimate the Vickers microhardness number andultimate compression strength of the present Al/SiC composites. Moreover, wear rateand friction coefficient tests, as tribological properties, of Al/SiC composites wereinvestigated under dry sliding conditions by a pin-on-disc test rig.Based on the experimental results, all the mechanical and tribological propertiesshowed significant improvement of pure Al with gradually increasing SiC content upto 10%. Relative density enhanced and reached the highest value of 98 % at 0.5 wt.%SiC content. Also, the microstructure examination showed that the dispersion of SiCparticles within the Al matrix was good and uniform. Hence, Vickers microhardnessnumber and ultimate compressive strength results of pure Al were enhanced by 66.5,and 50.53 %, respectively at SiC content of 5 wt.%. Moreover, the wear ratecharacteristics of Al/7.5 wt.% SiC composites were improved by 47.3, 47.6, and 40.9% at applied loads of 5, 10, and 15 N, respectively compared to pure matrix Al.Finally, the friction coefficient of pure Al was improved and reached their optimumvalues at the SiC content of 5 wt.% under applied loads of 5, 10, and 15 N.