High temperature tempering behaviors in a structural steel under high magnetic field

An as-quenched structural steel is tempered at 600 and 650 degreesC for 1 h without and with a 14-T magnetic field. The magnetic field can effectively prevent the directional growth of cementite along martensite plate boundaries and twin boundaries by increasing both the cementite/ferrite interfacial energy and the magnetostrictive strain energy. Finally, particle-like cementite is obtained. Moreover, the magnetic field can obviously retard the formation and growth of 'distortion-free' regions in the matrix, though without having any noticeable effect on the orientation distribution of the 'distortion-free' part. Investigating this subject contributes to the understanding of the way a magnetic field influences phase transformation in solid metallic materials. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.