The effect of residual porosity on the flow stress of particulate composites was studied for a composite in which it is possible to create high porosity (>60%) by using particle coatings. The material was a eutectic composition Sn–Pb solder with additions of intermetaliic CU6Sn5 particles. It was found that porosity affects the strength of these composites much less than for non-composites, an effect attributed to particle bonding during solidification. At the same time, residual porosity was found to inhibit strongly or even to prevent hardening of this material. A micromechanical model is developed which simulates this behaviour over a wide range of porosities.
MST/1928
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