Aligned two-phase structures in Fe-C alloys

One of the goals in the application of magnetic fields to steels has been the alignment of their microstructures along the fields, as this may lead to the control of the textures and mechanical properties. This kind of magnetic alignments has been studied extensively in magneto-rheological fluids and a wealth of experimental data is available. The application of a magnetic field to such fluids induces magnetic dipole and multipole moments on each magnetic particle embedded in a carrier fluid. Anisotropic magnetic forces between pairs of the particles promote the head-to-tail alignment of the moments and draws the particles into proximity. These attractive interparticle forces lead to the formation of chains, columns, or more complicated networks of particles aligned with the direction of the magnetic field. The formation of a similar structure is also known for interacting nonmagnetic polystyrene particles in a magnetized fluid. In this paper, the authors report the first observation of chains or columns of paramagnetic fcc phase nucleated in the ferromagnetic bcc phase of carbon steels during the {alpha}{yields}{gamma} inverse transformation in high magnetic fields.