Cold compaction of an aluminium/short fibre alumina powder composite
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Al-20Si-3 Cu-1 Mg-0.3 Fe (wt%) rapidly solidified powder homogeneously mixed with 0, 5,10 and 20 vol % Saffil alumina fibres, was subjected to cold uni-axial, single-action die-compression with progressively increasing pressures up to ∼ 400 MPa and intermediate relaxation. The powders with 0 and 20 vol % fibres were also compacted to this target pressure in single steps and the resulting densification curves were compared to the progressive series curves. The densification behaviour during tapping (jolting) of the different powders was studied. Densification data were compared with two general and widely quoted compaction equations, being those due to Konopicky-Shapiro and to Kawakita. Above critical pressures, good agreement of experimental data with these relations was found. The tapping process of densification of the materials could be described by the Kawakita relation. The effect of both tapping and rigid-die compaction on fibre size was evaluated. Mean fibre size was not significantly affected by the tapping treatment. The extent of breakage during die compaction depended on the applied pressure.
KeywordsPolymer Alumina Experimental Data Compaction Single Step
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