Author : Ahmed Moosa and Abbas Yass Awad

The present study deals with the wear behavior of Al-Re alloy/ RHA-Y2O3 hybrid composites. The Aluminum-Rare earth alloy (Al-Re) was used as a matrix to be reinforced with rice husk ash (RHA) and yttrium oxide (Y2O3). The Aluminum-Rare earth matrix alloy (Al-Re alloy) was prepared by melting 4032Al alloy with a standard Mg-Re alloy (AE42 alloy contains cerium and lanthanum) .The desired Al-Re alloy/ RHA-Y2O3 hybrid composites were produced by using two-steps stir casting process by adding RHA: Y2O3 in weight ratios 4:0, 3:1, 2:2, 1:3 and 0:4 to Al-Re alloy such that the total reinforcement is 10wt% . Dry sliding wear, coefficient of friction, hardness, apparent density, percentage of porosity were examined. The prepared hybrid composites were characterized using optical micrograph , SEM and X-ray diffraction. The addition of rare earth element (cerium and lanthanum) increases the hardness and the density and lowers the wear rate by decreasing the porosity in the matrix, refinement of the grains and the formation of intermetallic compounds such as Al3Ce, Al4Ce and La3Al11 in matrix. In general, the wear rates of the composites are lower than alloys especially at 20N.Coefficient of frictionvaries inversely with increasing both applied load and volume fraction of RHA. The Al-Re alloy-Y2O3 composites have minimum wear rate . Al-Re alloy-(RHA-Y2O3)[3:1] hybrid composites have lower porosity with more grains refinement.

Keywords: Aluminum, Rice Husk Ash, Yttrium oxide , Hybrid Metal Matrix Composites , Stir casting, Wear rate , Rare earth

Article published in International Journal of Current Engineering and Technology, Vol.6, No.3 (June-2016)