High pressure phase transformations revisited.

摘要: High pressure phase transformations play an important role in the search for new materials and material synthesis, as well geophysics. However, they are poorly characterized, transformation hysteresis vary drastically experiments of different researchers, with transmitting media, suppliers. Here we review current state, challenges studying under high pressure, possible ways overcoming challenges. This field is critically compared fields normal steels shape memory alloys, plastic deformation materials. The main reason above mentioned discrepancy lack understanding that there a fundamental difference between pressure-induced hydrostatic conditions, stress-induced nonhydrostatic conditions below yield, strain-induced during flow. Each these types has mechanisms requires completely thermodynamic kinetic description experimental characterization. In comparison other following indicated transformation: (a) initial evolving microstructure not included characterization transformations; (b) continuum theory developed; (c) heterogeneous stress strain determined, which leads to confusing transformational properties system behavior. Some advance suggested. key points are: take into account deformations evolution formulate criteria equations terms tensors (instead alone); develop multiscale theories, (d) couple experimental, theoretical, computational studies behavior tested sample extract information about concentration phase, kinetics. ideal should contain complete required simulation same experiments.