Characterization of a Functionally Graded Hypereutectic Al-Si Alloy Produced by Centrifugal Method
In the present study, Al-Si samples with a graded structure were produced via horizontal centrifugal casting. The distribution of primary and eutectic silicon particles within the produced specimens was investigated by optical microscopy. The microstructure of one end of the sample (closed to rotating axis) consisted of primary Si particles distributed within a eutectic matrix. The volume fraction of these particles decreased towards the other end of the sample and exhibited mostly primary Al-α and eutectic structure. Microhardness and macrohardness measurements conducted along the sample length showed a gradual decreasing value from one end (near the rotation axis) towards the other end of sample demonstrating functionally graded properties. These results were rationalized in terms of the lower density of Si compared to Al alloy which provided the movement of Si particles under the action of centrifugal forces during rotation.
Alan K.T. Lau, J. Lu, Vijay K. Varadan, F.K. Chang, J.P. Tu and P.M. Lam
E. Oveisi and F. Akhlaghi, "Characterization of a Functionally Graded Hypereutectic Al-Si Alloy Produced by Centrifugal Method", Advanced Materials Research, Vols. 47-50, pp. 865-868, 2008