Eun Jung Seo1,2, Lawrence Cho3, Jin Kyung Kim4, Javad Mola5, Lijia Zhao2, Sukjin Lee2, Bruno C De Cooman1. 1. Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang, 37673, South Korea. 2. Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, CO 80401, USA. 3. National Institute of Standards and Technology, Boulder, CO 80305, USA. 4. Department of Materials Sciences & Chemical Engineering, Hanyang University, Ansan, 15588, South Korea. 5. Materials Design and Structural Integrity Laboratory, Faculty of Engineering and Computer Sciences, Osnabrück University of Applied Sciences, 49076 Osnabrück, Germany.
Abstract
We report evidence of a displacive phase transformation from retained austenite to martensite during preparation of quenched and partitioned steel micro-pillars by using a focused ion beam (FIB) technique. The BCC phase produced by the FIB damage was identified as martensite. The invariant-plane strain surface relief associated with the martensitic transformation was observed in the retained austenite phase immediately after a FIB scan of the surface with the Ga+ ion beam. Use of a low acceleration voltage appears to lower the probability of the phase transformation, while a decrease of the acceleration voltage will result in an increase of the total milling time required to prepare a micro-pillar. This report addresses challenges related to the preparation of austenite micro-pillars by a conventional FIB technique.
We report evidence of a displacive phase transformation from retained austenite to martensite during preparation of quenched and partitioned class="Chemical">steel miclass="Chemical">pan class="Chemical">cro-pillars by using a focused ion beam (FIB) technique. The BCC phase produced by the FIB damage was identified as martensite. The invariant-plane strain surface relief associated with the martensitic transformation was observed in the retained austenite phase immediately after a FIB scan of the surface with the Ga+ ion beam. Use of a low acceleration voltage appears to lower the probability of the phase transformation, while a decrease of the acceleration voltage will result in an increase of the total milling time required to prepare a micro-pillar. This report addresses challenges related to the preparation of austenite micro-pillars by a conventional FIB technique.
Entities:
Keywords:
focused ion beam; martensitic transformation; micro-pillar compression; quenched and partitioned steel; retained austenite