Remaining of ϵ-iron structure at atmospheric pressure and superlattice formation by shearing at high pressure

Abstract

Transmission X-ray diffraction pattern of iron sheared at high pressure show rings whose interplanar spacings correspond to those of ϵ-iron and their integral multiple, in spite of the fact that it has been kept at atmospheric pressure for ∼3 months from the shearing. This and other related phenomena suggest that the pattern corresponds to the remains of the ϵ-iron structure in which superlattice formed. The volume of the specimen at atmospheric pressure after elapsing ∼3 months at atmospheric pressure from the shearing was 86% of that before the shearing.

Keywords:

• Iron
• High-pressure
• Shearing
• Crystal structure
• Metals and alloys
• Transformation

Acknowledgements

We express our hearty thanks to Dr. Ryuichi Habu and Dr. Munetsugu Matsuo of Japan Technical Information Service for their useful discussions and help. This work was carried out by joint research at the Institute for Study of the Earth's Interior, Okayama University.