Rapidly solidified Fe100-xGax （x=16-20） alloy rods were prepared by induction melting and copper mold casting under the protection of inert gases. The optical microscopy observation shows that the large and elongate...Rapidly solidified Fe100-xGax （x=16-20） alloy rods were prepared by induction melting and copper mold casting under the protection of inert gases. The optical microscopy observation shows that the large and elongated columnar grains grow along the radial direction, which is parallel to the temperature gradient direction. The preferred orientation texture along the axial direction of the rod was detected by XRD. With the increase of Ga content, the saturation magnetization （Ms） of the alloys decreases distinctly and the dynamic response in low magnetic field increases drastically, the maximum longitudinal saturation magnetostriction for as-cast Fe82Ga18 alloy rods is 92×10-6 under an applied magnetic field strength of 30 kA/m. The large magnetostriction of Fe100-xGax alloys is attributed to the rapidly solidified disordered A2 phase and the high concentration of short range order of Ga atom clusters, which are arranged in the direction and finally trigger the formation of modified-DO3 structure, just as shown by the split of the （200） diffraction peak. Ordered DO3 phase is not conducive to the magnetostriction.展开更多
The magnetic domain structures of the 100 oriented Fe 81 Ga 19 polycrystalline alloys with rapid quenching(RQ) and post-annealing(PA) thermal treatments are investigated by using magnetic force microscopy(MFM).The sur...The magnetic domain structures of the 100 oriented Fe 81 Ga 19 polycrystalline alloys with rapid quenching(RQ) and post-annealing(PA) thermal treatments are investigated by using magnetic force microscopy(MFM).The surfaces of the RQ alloy rods take on the dendritic domains after undergoing a standard mechanical polishing.While after PA processing,the distinct domain structures are observed at different temperatures.The wide stripe-like domain patterns appear in the surface of those PA rods at 550°C while the ramous domains remain at 400°C annealing.X-ray diffraction patterns indicate that a thin iron layer is formed on the surface of the specimens annealed at higher temperature.The soft magnetic iron layer,actually acting as a shield for the stray fields emerging from the internal magnetic structures underneath,brings about the presentation of the wide internal domains.展开更多
基金Project (11004091) supported by the National Natural Science Foundation of ChinaProject (Y4090219) supported by the Natural Science Foundation of Zhejiang Province, China+1 种基金Project (0916RJZA025) supported by the Natural Science Foundation of Gansu Province, ChinaProject (Q201104) supported by the "Hongliu Outstanding Youth" Foundation of Lanzhou University of Technology, China
文摘Rapidly solidified Fe100-xGax （x=16-20） alloy rods were prepared by induction melting and copper mold casting under the protection of inert gases. The optical microscopy observation shows that the large and elongated columnar grains grow along the radial direction, which is parallel to the temperature gradient direction. The preferred orientation texture along the axial direction of the rod was detected by XRD. With the increase of Ga content, the saturation magnetization （Ms） of the alloys decreases distinctly and the dynamic response in low magnetic field increases drastically, the maximum longitudinal saturation magnetostriction for as-cast Fe82Ga18 alloy rods is 92×10-6 under an applied magnetic field strength of 30 kA/m. The large magnetostriction of Fe100-xGax alloys is attributed to the rapidly solidified disordered A2 phase and the high concentration of short range order of Ga atom clusters, which are arranged in the direction and finally trigger the formation of modified-DO3 structure, just as shown by the split of the （200） diffraction peak. Ordered DO3 phase is not conducive to the magnetostriction.
基金supported partially by Hunan Provincial Science and Technology Department of China (Grant No. 2012WK3032)
文摘The magnetic domain structures of the 100 oriented Fe 81 Ga 19 polycrystalline alloys with rapid quenching(RQ) and post-annealing(PA) thermal treatments are investigated by using magnetic force microscopy(MFM).The surfaces of the RQ alloy rods take on the dendritic domains after undergoing a standard mechanical polishing.While after PA processing,the distinct domain structures are observed at different temperatures.The wide stripe-like domain patterns appear in the surface of those PA rods at 550°C while the ramous domains remain at 400°C annealing.X-ray diffraction patterns indicate that a thin iron layer is formed on the surface of the specimens annealed at higher temperature.The soft magnetic iron layer,actually acting as a shield for the stray fields emerging from the internal magnetic structures underneath,brings about the presentation of the wide internal domains.
