EFFECT OF GRAPHITE/WC ADDITIONS ON PHYSICAL, MECHANICAL, AND WEAR PROPERTIES OF ALUMINUM
DIYALA JOURNAL OF ENGINEERING SCIENCES,
2017, Volume 10, Issue 4, Pages 72-86
AbstractMetal matrix composites with based of Aluminum are considered among the most important ones that are used in complex engineering application for their good properties; including high resistance to weight ratio, low density, and wear resistance.
This work aims to make an Aluminum matrix composite that is reinforced with Tungsten Carbide (WC) particles with constant volumetric ratio of 3% in addition to Graphite particles (Gr) variable volumetric ratios of (0,2,4,6, and 8%) by using powder metallurgical techniques and study the physical, mechanical and wear properties of aluminum. The materials were mixed for 15 minutes using a mechanical mixer, then the mixture was cold compressed to 500 MPa to get samples with 12 mm in diameter, and 6 mm high, then they were sintered at 550 oC for two hours. Some mechanical properties were studied, hardness, compressive strength, wear rate; in addition to the physical properties of volumetric and apparent density, total and apparent porosity, water absorption, and microscopic structure examination.
The results showed that hardness and compressive strength were decreased by 24% and 40%, respectively by increasing the volumetric ratio of the graphite. Furthermore, the minimum wear rate, or maximum strength, was obtained at graphite ratio of 2%, then it increases after that, while the based composite reinforced with tungsten carbide only showed maximum wear rate and minimum resistance. Moreover, the results also showed that there is a proportional relationship between the volumetric and apparent densities in which they decrease when the volumetric ratio of the graphite increases. On the contrary, the total and apparent porosity increase by increasing graphite content, causing increase in water absorption for the hybrid composite.
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