CORRELATION OF MICROSTRUCTURE AND FLUIDITY PROPERTY OF SHORT FIBER-ALUMINUM ALLOY MATRIX COMPOSITES. A COMPARISON WITH THE UNREINFORCED MATRIX ALLOYS

摘要

This is a study of the fluidity property for AlCuSi/Al_2O_3 composites at the Al-rich corner. The fluidity measurements were carried out in terms of a classic foundry practice (i.e., the length the liquid metal flows in a channel packed with an alumina chopped fibers preform while solidifying: L_i). The fluidity mechanism was investigated with a focus on microstructure and the fluidity values of eutectics that complete solidification. The fluidity test results indicated that the infiltrated length was best in the alloys and composites situated in the primary Si field, followed by those situated in the primary Al field and solidified side of the Al-Cu eutectic valley and side of the Al-Si eutectic valley respectively. In all cases the results were found to be influenced by the morphology and concentrations of constituent phases in the microstructure and they were compared with the fluidity test results of the unreinforced matrix alloys. Quantitative metallography measurements are presented to substantiate such interpretations.