Grain refinement of steel by oxidic second phase particles

Abstract

Steels manufactured by a mechanical alloying and hot pressing route, to give a fine dispersion of alumina particles, have shown complete inhibition of grain growth after heating to 1350°C for 30 min, and in the near fusion line region of the heat affected zone of a bead on plate weldment. Comparison with theoretical predictions have shown that, with the 10 μm radius of the as transformed austenite grains, the observed grain growth inhibition would be predicted. The efficacy of these fine dispersions can be attributed to the high stability of the alumina which results in extremely small levels of dissolution of alumina in austenite, and which also severely curbs the coarsening of the dispersed alumina particles.