Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical properties.The steel was synthesized by Cu mold casting technique using 1-2N pure metals.Characterization of ...Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical properties.The steel was synthesized by Cu mold casting technique using 1-2N pure metals.Characterization of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron microscopy.The activation energies were calculated by Kissinger equation and it was found that the steel had better stability against crystallization.Mechanical properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were measured.It was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.展开更多
Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 , Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 and Fe55 Nb2 Cr12 Mo10 B6 C13 Y2 alloys with diameter of 4 mm were produced by copper mold casting. The effect of alloying additions （Ni, Cu or Nb） on corr...Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 , Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 and Fe55 Nb2 Cr12 Mo10 B6 C13 Y2 alloys with diameter of 4 mm were produced by copper mold casting. The effect of alloying additions （Ni, Cu or Nb） on corrosion resistance of Fe55 Nb2 Cr12 Mo10B6 C13 Y2, Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 and Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 alloys was studied by polarization curves and electrochemical impedance spectroscopy （EIS）. The results show that Fe55 Ni2 Cr12 Mo10 B6C13 Y2 and Fe55 Cu2 Crl2 MOl0 B6 C13 Y2 alloys can be cast to form bulk metallic glasses. Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 and Fe55 Cu2 Cr12 Mo10 86 C13 Y2 amorphous alloys with passive potential about 1 500 mV exhibit good corrosion resistance in NaCI solution of 5% and 1 mol/L HC1 solution. The passive current density of the alloy with Ni addition is lower than that of other alloys. EIS results only show one impedance element. Amorphous alloy Fe55 Ni2 Cr12 Mo10 B6C13 Y2 with larger charge transfer reaction resistance indicates good corrosion resistance.展开更多
Crystallization kinetics of Fe52Cr18Mo7B16C4Nb3 alloy was evaluated by X-ray diffraction（XRD）,differential scanning calorimetric（DSC） tests and transmission electron microscopy（TEM） observations in this research...Crystallization kinetics of Fe52Cr18Mo7B16C4Nb3 alloy was evaluated by X-ray diffraction（XRD）,differential scanning calorimetric（DSC） tests and transmission electron microscopy（TEM） observations in this research work.In effect,crystallization and growth mechanism were investigated by using DSC tests at four different heating rates（10,20,30,40 K/min）.Results showed that a two-step crystallization process occurred in the alloy in which α-Fe and Fe3B phases were crystallized,respectively in the structure after heat treatment.Activation energy for the first step of crystallization,i.e.α-Fe was measured to be 421 and 442 kJ/mol according to Kissinger-Starink and Ozawa models,respectively.Further,Avrami exponent calculated from DSC curves was 1.6 and a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was observed in the alloy.Moreover,it was known from the TEM observations that crystalline α-Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.展开更多
The flow-accelerated corrosion experiments were carried out to research the effect of Cr on the rust layers formed on the carbon steel and Cr-containing steel,as well as the structure of rust layer of the two experime...The flow-accelerated corrosion experiments were carried out to research the effect of Cr on the rust layers formed on the carbon steel and Cr-containing steel,as well as the structure of rust layer of the two experimental steels.The influence of Cr on the flow-accelerated corrosion resistance and the corrosion morphology of inner rust layer formed on the Cr-containing steel were studied by the methods of polarization curves,scanning electron microscope,transmission electron microscope,and X-ray photoelectron spectroscope.The distribution of Cr and its form of existence in the inner rust layer were analyzed.The results show that corroded mass loss of Cr-containing steel is lower than that of carbon steel and its inner rust layer is compact.Cr exists in the form of Fe2CrO4 and is enriched in the inner rust layer.This concentration could make the inner rust layer exhibit the tendency of amorphous.This phenomenon is related to fine Fe2CrO4.The inner rust layer becomes more compact because of the formation of fine Fe2CrO4,and the protectiveness of inner rust layer could be improved remarkably.展开更多
基金support provided by the Chinese Academy of Sciences
文摘Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical properties.The steel was synthesized by Cu mold casting technique using 1-2N pure metals.Characterization of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron microscopy.The activation energies were calculated by Kissinger equation and it was found that the steel had better stability against crystallization.Mechanical properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were measured.It was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.
基金Item Sponsored by Major Project Foundation of Beijing of China (D405003000021)
文摘Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 , Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 and Fe55 Nb2 Cr12 Mo10 B6 C13 Y2 alloys with diameter of 4 mm were produced by copper mold casting. The effect of alloying additions （Ni, Cu or Nb） on corrosion resistance of Fe55 Nb2 Cr12 Mo10B6 C13 Y2, Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 and Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 alloys was studied by polarization curves and electrochemical impedance spectroscopy （EIS）. The results show that Fe55 Ni2 Cr12 Mo10 B6C13 Y2 and Fe55 Cu2 Crl2 MOl0 B6 C13 Y2 alloys can be cast to form bulk metallic glasses. Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 and Fe55 Cu2 Cr12 Mo10 86 C13 Y2 amorphous alloys with passive potential about 1 500 mV exhibit good corrosion resistance in NaCI solution of 5% and 1 mol/L HC1 solution. The passive current density of the alloy with Ni addition is lower than that of other alloys. EIS results only show one impedance element. Amorphous alloy Fe55 Ni2 Cr12 Mo10 B6C13 Y2 with larger charge transfer reaction resistance indicates good corrosion resistance.
文摘Crystallization kinetics of Fe52Cr18Mo7B16C4Nb3 alloy was evaluated by X-ray diffraction（XRD）,differential scanning calorimetric（DSC） tests and transmission electron microscopy（TEM） observations in this research work.In effect,crystallization and growth mechanism were investigated by using DSC tests at four different heating rates（10,20,30,40 K/min）.Results showed that a two-step crystallization process occurred in the alloy in which α-Fe and Fe3B phases were crystallized,respectively in the structure after heat treatment.Activation energy for the first step of crystallization,i.e.α-Fe was measured to be 421 and 442 kJ/mol according to Kissinger-Starink and Ozawa models,respectively.Further,Avrami exponent calculated from DSC curves was 1.6 and a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was observed in the alloy.Moreover,it was known from the TEM observations that crystalline α-Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.
文摘The flow-accelerated corrosion experiments were carried out to research the effect of Cr on the rust layers formed on the carbon steel and Cr-containing steel,as well as the structure of rust layer of the two experimental steels.The influence of Cr on the flow-accelerated corrosion resistance and the corrosion morphology of inner rust layer formed on the Cr-containing steel were studied by the methods of polarization curves,scanning electron microscope,transmission electron microscope,and X-ray photoelectron spectroscope.The distribution of Cr and its form of existence in the inner rust layer were analyzed.The results show that corroded mass loss of Cr-containing steel is lower than that of carbon steel and its inner rust layer is compact.Cr exists in the form of Fe2CrO4 and is enriched in the inner rust layer.This concentration could make the inner rust layer exhibit the tendency of amorphous.This phenomenon is related to fine Fe2CrO4.The inner rust layer becomes more compact because of the formation of fine Fe2CrO4,and the protectiveness of inner rust layer could be improved remarkably.
