Advances in MA aluminium powders consolidation by mechanical cold pressing and vacuum sintering

Mechanically alloyed (MA) Al-based powder particles are difficult to consolidate. Oxide and hydroxide layers cover the surfaces of the hard MA particles, opposing to particle adhesion. Therefore, consolidation typically requires hot working, as the main process step. The authors research group has been developing a different consolidation route, comprising only cold pressing and vacuum sintering as main processing steps. Different conditions were experienced to improve compacts final properties, i.e., milling media and atmospheres, PCA, degassing, pressures, sintering aids, etc. Consolidated parts had relative densities and mechanical properties comparable to those obtained using hot-working processes. Properties were fairly maintained after long exposures at high temperatures.