Superplasticity and hardening of extremely fine grained ultrahigh carbon-chromium-vanadium-iron alloys

Microcrystalline ultrahigh carbon steels, alloyed with up to 20 wt% vanadium and chromium, have been prepared by melt atomization and powder metallurgical techniques. The resulting microstructure contains a large volume fraction of carbides and a grain size of less than 1 micron. At room temperature, these microcrystalline steels exhibit a high yield stress while maintaining adequate toughness for practical applications. Exposure to higher temperatures softens the material considerably and it becomes superductile. The large elongation to failure and the high value of the strain rate sensitivity, m = 0.5, indicate superior superplastic properties of these extremely fine grained materials