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

Document Type : Original Article

Authors

Production Technology Dept., Faculty of Technology and Education, Beni-Suef University, Beni-Suef, EGYPT.

Abstract

The present work aims to study the effect of SiC particles addition on the
microstructural, mechanical, and tribological properties of Al/SiC composites
produced by hot compaction powder metallurgy technique. High-energy planetary
ball milling was used for mixing the pure Al powder with different SiC particles
content of 2.5, 5, 7.5, and 10 wt.% at a speed of 350 rpm for 12 h. A hot compaction
technique was used to produce the present Al/SiC composites at a pressure and
temperature of 900 MPa and 550 ºC, respectively. Theoretical, actual, and relative
densities 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, were
conducted at room temperature to estimate the Vickers microhardness number and
ultimate compression strength of the present Al/SiC composites. Moreover, wear rate
and friction coefficient tests, as tribological properties, of Al/SiC composites were
investigated under dry sliding conditions by a pin-on-disc test rig.
Based on the experimental results, all the mechanical and tribological properties
showed significant improvement of pure Al with gradually increasing SiC content up
to 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 SiC
particles within the Al matrix was good and uniform. Hence, Vickers microhardness
number 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 rate
characteristics 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 optimum
values at the SiC content of 5 wt.% under applied loads of 5, 10, and 15 N.

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