Microstructure of Plasma-Sintered Aluminum Bronze Powder Compacts

Porous materials are successfully utilized for fabrication of many industrial components such as filters and selflubricating bearings. These products are made by powder metallurgy, where mixtured or prealloyed powders can be used. The aluminum bronze is one of the most wanted due its excellent properties in combination with low cost of the raw materials. In this work, single action compacted (100 MPa) prealloyed aluminum bronze (Cu- 9wt%Al-1wt%Fe) cylinders were sintered using a hollow cathode discharge at temperatures between 400 and 750°C with duration on the isotherm for 12 min. Microstructure changes, homogeneity, porosity and composition were analyzed after the treatment. Sintering below 550° C led to uniform but porous structure. Above 550 °C it was observed a solidified central region and a porous structure that changes slightly through out the cross-section. The diameter of the central region increased with treatment temperature. It is concluded that due to the intense plasma heating and subsequent surface melt formation a mass flow direction to the center of compacts occurred.