High saturation magnetic induction and low magnetostriction of a novel ferritic Fe-Ti alloy compared to a non-oriented silicon steel

Non-oriented (NO) silicon steel is used in magnetic cores of electrical machines due to its good magnetic and electric properties, such as high electric resistivity, high permeability, low coercive field, and low power losses. However, the noise and vibration, caused by magnetostriction, may lead to early failure of the equipment. Since the stator core is submitted to compressive stresses due to the shrinking fitting, positive values of magnetostriction are not appropriate. Fe-Ti alloys have low negative magnetostriction values making them strong candidates for replacing Fe-Si alloys. In this work, Fe-3wt.%Ti alloy was cold rolled down to 0.3 mm of thickness and annealed for 48 h at 850 °C. Magnetization showed to be 7 kA/m (0.09 T) higher than Fe-Si, and the magnetostriction is lower than 1 ppm up to 1.5 T while for Fe-Si is higher than 1 ppm for <0.25 T. Microstructure and texture were evaluated to explain the magnetic properties. The magnetic properties of Fe-3wt.%Ti are better than commercial non-oriented Fe-Si and could be an alternative to improve the performance of electrical motors.