Abstract
With a purpose of attesting preferential oxidation of an alloying element which has low solid solubility in Al, an Al-5at%Ca alloy was mechanically alloyed with or without addition of metal oxides. Ca was chosen as an alloying element since it shows higher oxidation tendency than Al and a low maximum solid solubility below 0.01mass% 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 the oxygen sources for internal oxidation and Ca in Al was shown to be preferentially oxidized to CaO and CaAl4O7. The P/M materials with addition of CuO showed high tensile strength of above 500MPa at room temperature.
