The Influence of Nanocrystalline Structure Of Iron On a-e Phase Transformations Under Pressure

摘要

We have studied features of a martensitic a(bcc)?￡(hcp) transformation under high pressure in iron of both coarse-grained and nanocrystalline condition. The use of spectroscopy methods of synchrotron radiation (SR) and nuclear gamma resonance (NGR) in combination with an in situ technique under pressure has allowed us to reveal the influence of a nanocrystalline structure in iron on the hysteresis of the phase transformation. An increase in the transformation hysteresis is proportional to the increase of strengthening attained in the nanocrystalline structure as a result of preliminary application of severe plastic deformation.