Abstract
With a purpose of attesting preferential oxidation of an alloying element which has low solid solubility in aluminum, an AI-5at%Y alloy was mechanically alloyed with or without addition of metal oxides. Y was chosen as an alloying element since it has higher oxidation tendency than Al and a low maximum solid solubility of 0.17mass% in Al. Mechanically alloyed powders were consolidated by hot-extrusion to the P/M materials of which constituent phases, microstructures and mechanical properties were examined. The added oxygen, either from the process control agent or from oxide powders, acted as oxygen sources for internal oxidation, and Y in Al was shown to be preferentially oxidized to Y2O3 and A15Y3O12. The P/M materials with addition of oxide powders showed high tensile strength of about 600MPa at room temperature.
