Consolidation Features of Aluminum-Alumina Compositions by Powder Metallurgy Methods

摘要

In this paper was followed the processing flow of aluminum-alumina compositions (10÷20wt.% alumina) in powder state, aiming to obtain aluminum matrix composites reinforced with alumina particles, starting from selecting and mixing the grading fraction of both components reaching up to sintering; it was analyzed the way in which reflects the variation of grading fraction ratio (expressed through average particle diameter in the analyzed fractions limits) on the level of technological interest features: apparent density, tapped density, flowability, presability and on densification after sintering (in various environments). By transmission electron microscopy was observed that aluminum particles showed on the surface a nanoscale oxide film, so the sintering occurs between congeneric areas - by solid phase sintering mechanisms. The analysis of thermophysical properties revealed a decrease of thermal diffusivity at an increase of alumina, simultaneous with the decrease of the densification level.