Influence of milling conditions on the wear resistance of mechanically alloyed aluminium

The tribological behaviour of mechanically alloyed (MA) aluminium-base materials has been studied as a function of processing conditions. [MA Al–NH3], milled under an ammonia atmosphere in the presence of 3.0 wt.% of ethylene-bisstearamide as process control agent (PCA) and consolidated by a single cycle of cold compaction and sintering, is compared with two MA aluminium materials ([MA Al–air 1.5] and [MA Al–air]), milled in confined air in the presence of 1.5 and 3.0 wt.% of PCA, respectively, and consolidated by a double cycle of compaction and sintering. Elemental aluminium [Al-1], processed by a similar press-and-sinter double cycle, has also been studied as reference material. Milling in ammonia gas and in the presence of 3.0 wt.% PCA increases the critical load and temperature for transitions in wear regimes. Wear mechanisms are discussed from SEM observation of wear tracks, wear debris, transfer tribolayers and EDS analysis.