EXTRUSÃO A QUENTE DE LIGAS DE ALUMÍNIO NANOESTRUTURADAS EM PÓ: EFEITO DA PRECIPITAÇÃO NO CONTROLE MICROESTRUTURAL

Three nanostructured aluminium-powder alloys were utilized as follows: a) supersaturated Al-4.5%Cu prepared by rapid solidification and mechanical-alloying; b) non-supersaturated Al-3.0%Fe, rich in precipitates, prepared by rapid solidification via gas atomization; and c) non-supersaturated 6061 Al alloy, rich in precipitates, prepared by rapid solidification via gas atomization and reinforced with Si3N4 particles). The three different alloys were consolidated into bulk material under various processing conditions via hot extrusion. The microstructure modifications of the consolidated alloys as a function of the extrusion conditions were discussed and investigated. The effect of the pre-existent precipitates from non-supersaturated alloys is shown to be more effective to grain growth controlling. The increase in the extrusionload with the increase of extrusion-rate and decrease of temperature are discussed in association with the modification in the microstructures