Stability of the austenitic phase in ultra-fine particles of Fe-based alloys

The effect of the ultra-fine particle size of Fe-based alloys on the marten sitic transformation was analyzed qualitatively. It is shown that the stabi lities of the austenitic phase and the martensitic phase are reversed as th e particle size becomes smaller than a given critical value. The austenitic phase may become more stable than the martensitic phase and the martensiti c transformation cannot take place even when cooled to temperatures approac hing 0 K. This may be the main reason why nanocrystalline morphologies may prevent martensitic transformation. (C) 2001 Elsevier Science B.V. All righ ts reserved.