Wear characteristics of spray formed Al-alloys and their composites

In the present investigation, different Al based
alloys such as Al–Si–Pb, Al–Si, Al–Si–Fe and 2014Al ?
SiC composites have been produced by spray forming
process. The microstructural features of monolithic alloys
and composite materials have been examined and their
wear characteristics have been evaluated at different loads
and sliding velocities. The microstructural features invariably showed a significant refinement of the primary phases and also modification of secondary phases in Al-alloys.
The Pb particles in Al–Si–Pb alloy were observed to be
uniformly distributed in the matrix phase besides decorating the grain boundaries. The spray formed composites showed uniform distribution of SiC particles in the matrix.
It was observed that wear resistance of Al–Si alloy
increases with increase in Pb content; however, there is not much improvement after addition of Pb more than 20%.
The coefficient of friction reduced to 0.2 for the alloy
containing 20%Pb. A sliding velocity of 1 ms-1 was
observed to be optimum for high wear resistance of these
materials. Alloying elements such as Fe and Cu in Al–Si
alloy lead to improved wear resistance compared to that of
the base alloy. The addition of SiC in 2014Al alloy gave
rise to considerable improvement in wear resistance but
primarily in the low pressure regime. The wear rate seemed
to decrease with increase in sliding velocity. The wear
response of the materials has been discussed in light of
their microstructural features and topographical observation of worn surfaces.