A powder metallurgical process is provided for oxyreaction strengthening of metals in which ultrafine oxide particles are dispersed throughout a formed article after sintering. The matrix metal powder containing small amounts of oxygen is blended with a small amount of reactive metal powder, and the mixture is compacted and sintered. The reactive metal reacts with oxygen to form a coarse metal oxide. During heat treatment, ultrafine (0.05-0.2 Micrometer) reactive metal oxide particles form throughout the base metal. Preferred base metals include W, Mo, and their alloys, while preferred reactive metals include Si, Al, and group IVB elements of the periodic table.