Effect of the addition of different concentrations of particulate reinforcement on the density, hardness and wear resistance of aluminum composites produced by powder metallurgy

Abstract

The objective of this work is to evaluate the influence of the addition of different concentrations of particulate reinforcement in the production of commercially pure aluminum composites reinforced with blast-furnace slag via powder metallurgy. The processing of these materials was done by sieving, mixing and compacting powders of reinforced aluminum with 5, 10 and 15% of blast-furnace slag. The cold uniaxial compaction was realized at a pressure of 430 MPa. The obtained materials were sintered at 610°C for 2h under inert atmosphere. Unreinforced aluminum samples were also produced. The characterization of the materials was realized by density and microhardness measurements and wear tests. The morphological analysis was realized by scanning electron microscopy. As results, the materials had a relative density greater than 93,8%, reaching 98,6% for pure aluminum. The composites showed a homogeneous distribution of reinforcement particles and progressive improvement in microhardness with increasing slag concentration. However, regarding wear resistance, the result was the opposite. This result suggests that the reinforcing particles, being made of ceramic material, may have worked as an abrasive when released from the aluminum matrix, since commercially pure aluminum is extremely malleable and cannot hold the slag particles.