In situ phase transformation and deformation of iron at high pressure and temperature

With a membrane based mechanism to allow for pressure change in a sample in a radial diffraction diamond anvil cell and simultaneous infrared laser heating, it is now possible to investigate texture changes during deformation and phase transformations over a wide range of temperature-pressure conditions. The device is used to study bcc , fcc , and hcp iron. In bcc iron, room temperature compression generates a texture characterized by 100 and 111 poles parallel to the compression direction. During the deformation induced phase transformation to hcp iron, a subset of orientations is favored to transform to the hcp structure first and generate a texture of 011̄0 at high angles to the compression direction. Upon further deformation, the remaining grains transform, resulting in a texture that obeys the Burgers relationship of 110 bcc / / 0001 hcp. Contrary to these results for low temperature, at high temperature texture is developed through dominant pyramidal a+c 21̄1̄2 21̄1̄3 and basal 0001 21̄1̄0 slip based on polycrystal plasticity modeling. We also observe that the high temperature fcc phase develops a 110 texture typical for fcc metals deformed in compression. © 2008 American Institute of Physics. DOI: 10.1063/1.3008035