International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Dry sliding wear behaviour of unreinforced Al4%Cu and Al4%Cu – SiC composites was investigated. Composites containing 10-50 vol.% SiC were obtained via hot press by using Al, Cu and SiC starting powders. Wear tests were conducted by an oscillating tribometer having a 6 mm diameter alumina ball. 2 N load was employed and sliding span was 5 mm with a total test distance of 6 m. Wear tracks were examined by an optical microscope, track cross sectional areas were determined by a profilometer and wear rates were calculated. It was seen that the wear track formed on the unreinforced sample was much larger and deeper than the ones on the composite samples. Wear mechanism was suggested to be initially adhesive and then adhesive and abrasive. The wear rate of unreinforced sample was about 11×10^-3 mm³/N.m. Wear rate was seen to decrease abruptly with the addition of SiC particles into the matrix alloy. When 10 vol.% SiC was used, wear rate decreased to 1.5×10^-3 mm³/N.m. The lowest wear rate was achieved in the sample containing 30 vol.% SiC, 0.5×10^-3 mm³/N.m.

Metal matrix composites, containing Al (4 wt.% Cu) as the matrix material and SiC particles as the reinforcement, were produced by hot pressing. SiC(p) content of the composites were in 10 – 50 vol.% range. Appropriate amounts of Al, Cu and SiC powder were dry mixed and pressed at 25MPa at 525 and 550^oC. Obtained composites were subjected to density and hardness measurements, 3 point bending tests and optical microscope investigations. Hardness was seen to increase continuously with the increase in the amount of SiC(p) from 54HB10 (unreinforced matrix) to 148HB10 (50 vol.% SiC). On the other hand, bending strength values of the composites first showed an increase up to 20 vol.% SiC and then decreased. Strain values decreased considerably, with the addition of SiC into the unreinforced matrix and the composites containing 40 and 50 vol.% SiC did not show plastic deformation before fracture. Yield strength and elastic moduli of the composites increased with the increase in the SiC amount. It was seen that the properties of Al%4Cu-SiC(p) composites, such as strength and hardness, can be adjusted by varying their SiC contents.