Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was propos...Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.展开更多
Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer...Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.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Joint Funds of the National Natural Science Foundation of China(U20A20293)。
文摘Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.
基金supported by the National Natural Science Foundation of China (Grant Nos.60577030,60776041,60876035)the National Key Basic Research Special Foundation of China (Grant Nos.TG2007CB307004,2006CB921607)
文摘Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.
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.
