The room temperature compressive plasticity of Fe75MosP10Cs.3B1.7 bulk metallic glass (BMG) was improved from 0.5% to 1.8% by increasing the sample diameter from 1.5 mm to 2.0 mm. With increasing the sample diameter...The room temperature compressive plasticity of Fe75MosP10Cs.3B1.7 bulk metallic glass (BMG) was improved from 0.5% to 1.8% by increasing the sample diameter from 1.5 mm to 2.0 mm. With increasing the sample diameter to 2.0 mm, a heterogeneous microstructure with in-situ formed a-Fe dendrite sparsely distributed in the amorphous matrix can be attained. This heterogeneous mierostructure is conceived to be highly responsible for the enhanced global plasticity in this marginal Fe-based BMG.展开更多
The microstructural evolution of a Mg-10Ni-2Mm(molar fraction,%)(Mm=Ce,La-rich mischmetal) hydrogen storage alloys applied with various solidification rates was studied.The results show that the grain size of melt...The microstructural evolution of a Mg-10Ni-2Mm(molar fraction,%)(Mm=Ce,La-rich mischmetal) hydrogen storage alloys applied with various solidification rates was studied.The results show that the grain size of melt-spun ribbon is remarkably reduced by increasing the solidification rate.The microcrystalline,nanocrystalline and amorphous microstructures are obtained by applying the surface velocities of the graphite wheel of 3.1,10.5 and 20.9 m/s,respectively.By applying the surface velocity of the graphite wheel of 3.1 m/s,the melt-spun specimen obtains full crystalline with a considerable amount of coarse microcrystalline Mg and Mg2Ni except for some Mm-rich particles.The amount of nanocrystalline phases significantly increases with increasing the surface velocity of the wheel to 10.5 m/s,and the microstructure is composed of a large amount of nanocrystalline phases of Mg and Mg2Ni particles.A mixed microstructure containing amorphous and nanocrystalline phases is obtained at a surface velocity of the wheel of 20.9 m/s.The optimal microstructure with a considerable amount of nanocrystalline Mg and Mg2Ni in an amorphous matrix is expected to have the maximum hydrogen absorption capacity and excellent hydrogenation kinetics.展开更多
Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological ...Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability (GFA) and supercooled liquid region (ATx). The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ATX. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.展开更多
Ternary nickel cobaltite(NiCo2O4),as a promising electrode material for supercapacitors,has attracted increasing attention for its excellent electrochemical properties.In this study,novel NiCo2O4 nanosheets were ratio...Ternary nickel cobaltite(NiCo2O4),as a promising electrode material for supercapacitors,has attracted increasing attention for its excellent electrochemical properties.In this study,novel NiCo2O4 nanosheets were rationally designed and prepared using dealloying process,followed by an oxidation treatment.The as-prepared sample was characterized by microstructural and electrochemical techniques in view of its possible application in supercapacitors.The as-prepared sample exhibited high specific capacitance and excellent durability.The specific capacitance reached 663 F/g at 1 A/g and the rate capacitance high up to 73.6%when the current density increased from 1 A/g to 20 A/g.After 5000 cycles of galvanostatic charge-discharge durability test at 4 A/g,the capacity retention rate was 82.1%.The results indicate that versatile dealloying can be used to prepare robust electrode for supercapacitor application.展开更多
In this paper,SmCo6.9 Hf0.1 as-cast alloys and ribbons with the addition of either graphite(C) or carbon nanotubes(CNTs) were prepared by arc melting and melt-spinning,respectively.The effects of adding carbon on ...In this paper,SmCo6.9 Hf0.1 as-cast alloys and ribbons with the addition of either graphite(C) or carbon nanotubes(CNTs) were prepared by arc melting and melt-spinning,respectively.The effects of adding carbon on the structure and magnetic properties SmCo6.9 Hf0.1 were investigated by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),magnetic force microscopy(MFM) and vibrating sample magnetometer(VSM).It was found that the microstructure and magnetic structure of SmCo6.9 Hf0.1 ribbons were changed obviously due to the introduction of C or CNTs,although their crystal structure was characterized as the same Sm(Co,Hf)7 single phase,no matter carbon was added or not.As a result,the magnetic properties of carbon-contained ribbons were enhanced in a certain degree.This was considered to be related to the refined equiaxed grains,small domain size and the pinning effect of C or CNTs-rich regions.The magnetic properties of SmCo6.9 Hf0.1(CNTs)0.05 ribbons reached Hc =12.5 kOe,Mr =57.0 emu/g and Mr/M2 T =0.788.展开更多
基金Foundation item: Project (SWU110046) supported by the Startup Foundation for Doctors of Southwest University, ChinaProjects (XDJK2012C017,CDJXS11132228, CDJZR10130012) supported by the Fundamental Research Funds for the Central Universities, China+1 种基金Project (CSTS2006AA4012) supported by the Chongqing Science and Technology Commission, ChinaProject (T201112) supported by Shenzhen Key Laboratory of Special Functional Materials,Shenzhen University,China
文摘The room temperature compressive plasticity of Fe75MosP10Cs.3B1.7 bulk metallic glass (BMG) was improved from 0.5% to 1.8% by increasing the sample diameter from 1.5 mm to 2.0 mm. With increasing the sample diameter to 2.0 mm, a heterogeneous microstructure with in-situ formed a-Fe dendrite sparsely distributed in the amorphous matrix can be attained. This heterogeneous mierostructure is conceived to be highly responsible for the enhanced global plasticity in this marginal Fe-based BMG.
基金Project(2007DFA50590)supported by the International S&T Cooperation Projects the Norwegian Research Council for financial support
文摘The microstructural evolution of a Mg-10Ni-2Mm(molar fraction,%)(Mm=Ce,La-rich mischmetal) hydrogen storage alloys applied with various solidification rates was studied.The results show that the grain size of melt-spun ribbon is remarkably reduced by increasing the solidification rate.The microcrystalline,nanocrystalline and amorphous microstructures are obtained by applying the surface velocities of the graphite wheel of 3.1,10.5 and 20.9 m/s,respectively.By applying the surface velocity of the graphite wheel of 3.1 m/s,the melt-spun specimen obtains full crystalline with a considerable amount of coarse microcrystalline Mg and Mg2Ni except for some Mm-rich particles.The amount of nanocrystalline phases significantly increases with increasing the surface velocity of the wheel to 10.5 m/s,and the microstructure is composed of a large amount of nanocrystalline phases of Mg and Mg2Ni particles.A mixed microstructure containing amorphous and nanocrystalline phases is obtained at a surface velocity of the wheel of 20.9 m/s.The optimal microstructure with a considerable amount of nanocrystalline Mg and Mg2Ni in an amorphous matrix is expected to have the maximum hydrogen absorption capacity and excellent hydrogenation kinetics.
基金supported by the National Basic Research Program of China (Grant No. 2007CB613900)the National Natural Science Foundation of China (Grant No. 51071008)the Fundamental Research Funds for the Central Universities
文摘Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability (GFA) and supercooled liquid region (ATx). The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ATX. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.
基金Supported by the National Natural Science Foundation of China(No.51661018).
文摘Ternary nickel cobaltite(NiCo2O4),as a promising electrode material for supercapacitors,has attracted increasing attention for its excellent electrochemical properties.In this study,novel NiCo2O4 nanosheets were rationally designed and prepared using dealloying process,followed by an oxidation treatment.The as-prepared sample was characterized by microstructural and electrochemical techniques in view of its possible application in supercapacitors.The as-prepared sample exhibited high specific capacitance and excellent durability.The specific capacitance reached 663 F/g at 1 A/g and the rate capacitance high up to 73.6%when the current density increased from 1 A/g to 20 A/g.After 5000 cycles of galvanostatic charge-discharge durability test at 4 A/g,the capacity retention rate was 82.1%.The results indicate that versatile dealloying can be used to prepare robust electrode for supercapacitor application.
基金supported by General Program from the National Natural Science Foundation of China(51271072)National Science Fund for Young(51301056)+1 种基金Key Program from the Science and Technology Research for Colleges and Universities in Hebei Province(ZH2011202)Hebei Natural Science Foundation of China(E2013202030)
文摘In this paper,SmCo6.9 Hf0.1 as-cast alloys and ribbons with the addition of either graphite(C) or carbon nanotubes(CNTs) were prepared by arc melting and melt-spinning,respectively.The effects of adding carbon on the structure and magnetic properties SmCo6.9 Hf0.1 were investigated by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),magnetic force microscopy(MFM) and vibrating sample magnetometer(VSM).It was found that the microstructure and magnetic structure of SmCo6.9 Hf0.1 ribbons were changed obviously due to the introduction of C or CNTs,although their crystal structure was characterized as the same Sm(Co,Hf)7 single phase,no matter carbon was added or not.As a result,the magnetic properties of carbon-contained ribbons were enhanced in a certain degree.This was considered to be related to the refined equiaxed grains,small domain size and the pinning effect of C or CNTs-rich regions.The magnetic properties of SmCo6.9 Hf0.1(CNTs)0.05 ribbons reached Hc =12.5 kOe,Mr =57.0 emu/g and Mr/M2 T =0.788.