Αl- (Al 9 Co 2 , Al 13 Co 4 ) Powder Metallurgy Processed Composite Materials: Analysis of Microstructure, Sliding Wear and Aqueous Corrosion

Abstract

The present effort was undertaken in order to investigate the manufacturing of aluminum based composites, reinforced by a dual intermetallic phase, Al 9Co2 - Al 13Co4, using a powder metallurgy route. The metal matrix was reinforced with compositions 2, 5 and 10% vol. The manufacturing of the dual Al 9Co2 - Al 13Co4 powders was carried out by vacuum arc melting followed by milling to produce fine-sized powders. The composite materials were produced by a common powder metallurgy route, including mixing in a mortar, consolidation by cold pressing, and sintering under vacuum at 600°C. The wear properties of the composite were examined by dry sliding wear against an alumina counter face at 10cm/s, a load at 1N and a distance at 1000m. Macro hardness was also assessed. Aqueous corrosion experiments in 3.5% NaCl at 25°C were carried out in all three different compositions. Optical microscopy and SEM- EDX analysis were used in order to ascertain the microstructure, the sliding wear tacks and debris and the corroded surfaces. The sliding wear phenomena were related to the microstructural features and approached based on classic theories of Al composite wear behaviour and so was the corrosion response of the produced materials.