The microstructure and electrochemical characteristics of Ml(NiCoMnAl) 5 alloys prepared by both the melt spinning method and the conventional induction melting were investigated and compared. SEM and XRD studies sh...The microstructure and electrochemical characteristics of Ml(NiCoMnAl) 5 alloys prepared by both the melt spinning method and the conventional induction melting were investigated and compared. SEM and XRD studies show that the microstructure of melt spinning alloys is columnar structure. With increasing melt spinning rate, the crystal grains become finer and preferentially grow along (111)[111] direction. The melt spinning and cast alloys belong to CaCu 5 type hexagonal crystal structure. The electrochemical measurements show that the initial capacities of melt spinning alloy electrodes are all above 210 mAh·g -1 with good activation behavior, reaching their maximum capacities after two charge discharge cycles. The maximum capacity (294 mAh·g -1 ) of melt spinning (10 m·s -1 ) alloy electrodes is as the same as that of as cast alloy electrode, and stability of charge discharge cycles of all melt spinning alloy electrodes is better than that of the as cast alloy electrodes. When charged at 600 mA·g -1 , the capacity of melt spinning (10 m·s -1 ) alloy electrode could reach 65% of its maximum capacity about 45 min with high rate discharge capability; but with the cycle number increasing, the stability of its capacity is less than that electrodes of melt spinning rate.展开更多
The aim of this study is to investigate the surface quality of the melt spinning wheel, which was changed from smooth type to textured structure, to atomize liquid metal to form powders. The effects of melt spinning p...The aim of this study is to investigate the surface quality of the melt spinning wheel, which was changed from smooth type to textured structure, to atomize liquid metal to form powders. The effects of melt spinning process parameters like wheel speed, gas ejection pressure, molten metal temperature, nozzle–wheel gap and wheel surface quality on the morphological and microstructural features of 6060 aluminum alloy powders and ribbons were investigated. It was observed that ribbon type material was obtained with the smooth wheel and the powder was produced with textured type. The sizes of produced ribbons with smooth surface wheel varied in the range of 30-170 μm in thickness, 4-8 mm in width, and 0.5-1 m in length. The average powder size of the powders manufactured using the textured wheel was in the range of 161-274 μm, depending on the process parameters.Increasing the wheel speed, melt temperature and decreasing gas ejection pressure, nozzle-wheel gap resulted in the decrease of both ribbon thickness and powder size. The microstructures of the powders and ribbons were the equiaxed cellular type, and the average grain sizes diminished with decreasing the ribbon thickness and powder size. The maximum cooling rates were 2.00×10^5 and 1.26×10^4 K/s for the ribbon with thickness of 30 μm and for the powder with size of 87 μm, respectively.展开更多
A number of Fe-Si-B amorphous ribbons are made by using melt spinning method. The microstructure, mechanical and other relevant properties of thin amorphous ribbons of Fe81.50B1.40Si7.95Nb7.37Cu1.73P0.05 alloy at room...A number of Fe-Si-B amorphous ribbons are made by using melt spinning method. The microstructure, mechanical and other relevant properties of thin amorphous ribbons of Fe81.50B1.40Si7.95Nb7.37Cu1.73P0.05 alloy at room temperature were studied with several equipment including Differential scanning calorimetry (DSC), X-ray diffraction (XRD),Scanning electron microscope (SEM), and tensile machine. Significantly different microstructures exist between the free and wheel face of the thin amorphous ribbons. The free face is smooth while the wheel face is coarse with a great number of micro voids on the surface. Experimental results show that the tensile strength and elastic modulus of thethin amorphous ribbons at room temperature are 1951 MPa and 70 GPa. In addition, the amorphous ribbons possess reasonable tensile elongation (2.46%). The fracture appearance of amorphous ribbons of Fe81.50B1.40Si7.95Nb7.37Cu1.73P0.05 alloyis a mixed mode of ductile and brittle fracture which includes dimples and partial cleavage fracture similar to the crystalline materials. The dimple feature proves that it still has plastic characteristics on the micro scale.展开更多
文摘The microstructure and electrochemical characteristics of Ml(NiCoMnAl) 5 alloys prepared by both the melt spinning method and the conventional induction melting were investigated and compared. SEM and XRD studies show that the microstructure of melt spinning alloys is columnar structure. With increasing melt spinning rate, the crystal grains become finer and preferentially grow along (111)[111] direction. The melt spinning and cast alloys belong to CaCu 5 type hexagonal crystal structure. The electrochemical measurements show that the initial capacities of melt spinning alloy electrodes are all above 210 mAh·g -1 with good activation behavior, reaching their maximum capacities after two charge discharge cycles. The maximum capacity (294 mAh·g -1 ) of melt spinning (10 m·s -1 ) alloy electrodes is as the same as that of as cast alloy electrode, and stability of charge discharge cycles of all melt spinning alloy electrodes is better than that of the as cast alloy electrodes. When charged at 600 mA·g -1 , the capacity of melt spinning (10 m·s -1 ) alloy electrode could reach 65% of its maximum capacity about 45 min with high rate discharge capability; but with the cycle number increasing, the stability of its capacity is less than that electrodes of melt spinning rate.
文摘The aim of this study is to investigate the surface quality of the melt spinning wheel, which was changed from smooth type to textured structure, to atomize liquid metal to form powders. The effects of melt spinning process parameters like wheel speed, gas ejection pressure, molten metal temperature, nozzle–wheel gap and wheel surface quality on the morphological and microstructural features of 6060 aluminum alloy powders and ribbons were investigated. It was observed that ribbon type material was obtained with the smooth wheel and the powder was produced with textured type. The sizes of produced ribbons with smooth surface wheel varied in the range of 30-170 μm in thickness, 4-8 mm in width, and 0.5-1 m in length. The average powder size of the powders manufactured using the textured wheel was in the range of 161-274 μm, depending on the process parameters.Increasing the wheel speed, melt temperature and decreasing gas ejection pressure, nozzle-wheel gap resulted in the decrease of both ribbon thickness and powder size. The microstructures of the powders and ribbons were the equiaxed cellular type, and the average grain sizes diminished with decreasing the ribbon thickness and powder size. The maximum cooling rates were 2.00×10^5 and 1.26×10^4 K/s for the ribbon with thickness of 30 μm and for the powder with size of 87 μm, respectively.
基金Sponsored by the National Science Foundation of Anhui Province(Grant Nos.1508085ME84 and KJ2016A146)
文摘A number of Fe-Si-B amorphous ribbons are made by using melt spinning method. The microstructure, mechanical and other relevant properties of thin amorphous ribbons of Fe81.50B1.40Si7.95Nb7.37Cu1.73P0.05 alloy at room temperature were studied with several equipment including Differential scanning calorimetry (DSC), X-ray diffraction (XRD),Scanning electron microscope (SEM), and tensile machine. Significantly different microstructures exist between the free and wheel face of the thin amorphous ribbons. The free face is smooth while the wheel face is coarse with a great number of micro voids on the surface. Experimental results show that the tensile strength and elastic modulus of thethin amorphous ribbons at room temperature are 1951 MPa and 70 GPa. In addition, the amorphous ribbons possess reasonable tensile elongation (2.46%). The fracture appearance of amorphous ribbons of Fe81.50B1.40Si7.95Nb7.37Cu1.73P0.05 alloyis a mixed mode of ductile and brittle fracture which includes dimples and partial cleavage fracture similar to the crystalline materials. The dimple feature proves that it still has plastic characteristics on the micro scale.
