Effects of lubrication and aspect ratio on the consolidation of metal matrix composites under cyclic pressure Original Research Article

The effects of powder compaction under cyclic load were compared to traditional single-cycle compaction. The effect of interparticle friction as modified by lubrication and compact aspect ratio received particular attention. Mixtures of Al and Al2O3 were consolidated at room temperature in contained uniaxial consolidation experiments. The experiments showed that in static compaction, lubrication aids densification at low pressures but can inhibit consolidation at high pressures. Enhanced densification was observed following pressure cycling. These improvements were more pronounced in compacts having smaller aspect ratios. The efficiency of pressure cycling was reduced by the lubricant. Lubrication also decreased the effects of aspect ratio in both the static and cyclic compaction cases. Although lubrication did increase density uniformity, the resulting compact green strength was much lower. Both single and double action compaction were studied and the best green strength and density distribution were obtained with double-action compaction under cyclic pressure without lubricant.