9414525 Sehitoglu This research is primarily an experimental effort to further the understanding of stress- and strain-induced phase transformations under high pressures and cyclic loading in alloy steels. Pressure loading permits isolation of hydrostatic stress and principle stress effects on transformations and produces homogeneous stress fields allowing unambiguous interpretation of stress and strain effects. Cyclic loading modifies the internal structure and will generate different transformation behavior compared to unidirectional loading. The development of constitutive models based on a verified by well characterized experimental results is a very high priority in the Mechanics and Materials Program. Therefore, the experimental study of phase changes contained in this proposal is very important for establishing the data base that is required before the foundation for a strong theoretical component can be established. The proposed work will advance both the micro- and mechanical understanding of phase transformations in material systems. ***
