Crystal growth of high magnetostrictive polycrystalline Fe81Ga19 alloys

• Published in: Journal of magnetism and magnetic materials 2012-03, Vol.324 (6), p.1177-1181
• Main Authors: Li, Chuan, Liu, Jinghua, Wang, Zhibin, Jiang, Chengbao
• Format: Article
• Language: English
• Subjects: Compositional distribution; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Crystallographic orientation; Directional solidification; Exact sciences and technology; FeGa alloys; Growth from melts; zone melting and refining; Magnetic properties and materials; Magnetomechanical and magnetoelectric effects, magnetostriction; Magnetostriction; Materials science; Methods of crystal growth; physics of crystal growth; Physics
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2011.11.004

High magnetostrictive Fe81Ga19 alloy was prepared by induction heating zone melting method. The microstructure, solute partition behaviour, orientation evolution and magnetostriction are investigated. During the crystal growth process, the initial small grains gradually grow into large columnar crystals, and the solid–liquid interface shows slightly concave morphology. The equilibrium solute partition coefficient (k0), effective solute partition coefficient (ke) and solution diffusion coefficient (D) are calculated to be 0.74, 0.76 and 1.04×10−9m2/s, respectively. In the steady growth stage, the composition distribution of the FeGa rod is uniform with average level about 18.50at% Ga, which is close to the nominal composition. The deviation of the 〈001〉 orientation from the axial direction evolves from about 8° to 3° along the growth direction, and the corresponding magnetostriction increases from the initial 180ppm to the final 305ppm. ► Induction zone melting method was used to prepare high magnetostrictive polycrystalline Fe81Ga19 alloys. ► High magnetostriction of Fe81Ga19 polycrystalline up to 300ppm was achieved. ► Solute partitioning behaviour and composition distribution are investigated. ► Influence of the composition and the crystallographic orientation on the magnetostriction of FeGa is revealed.