Non-isothermal aging(NIA)is a composite heat treatment process that involves heating aging,cooling aging,and complex solute precipitation sequences.The precipitation behavior and the strengthening and toughening mecha...Non-isothermal aging(NIA)is a composite heat treatment process that involves heating aging,cooling aging,and complex solute precipitation sequences.The precipitation behavior and the strengthening and toughening mechanisms of the 2014 Al alloy during NIA were studied by employing tensile,fatigue crack growth,hardness,and electronic conductivity tests,as well as high-resolution transmission electron microscopy and scanning electron microscopy.The results show that during NIA,theθ′phase exhibits a complex process of nucleation,nucleation and growth,nucleation and growth and coarsening,growth and coarsening,nucleation and growth,and nucleation.NIA treatment imparts a mixed precipitation characteristic on the alloy,which is manifested as coherent precipitates,including GP zones,θ′′phases,small-sizedθ′phases,and semi-coherent or non-coherent precipitates such as large-sizedθ′phases and equilibriumθphases.The simultaneous strengthening and toughening of the NIA-treated 2014 Al alloy is caused by the synergistic effects of the particle-shearing mechanism and Orowan bypassing mechanism.展开更多
(Zr_(53)Al_(11.6)Ni_(11.7)Cu_(23.7))_(1−x)(Fe_(77.1)C_(22.9))_(x)(x=0−2.2,at.%)bulk metallic glasses(BMGs)were prepared by copper mold suction casting method.Their glass forming ability and physical and chemical prope...(Zr_(53)Al_(11.6)Ni_(11.7)Cu_(23.7))_(1−x)(Fe_(77.1)C_(22.9))_(x)(x=0−2.2,at.%)bulk metallic glasses(BMGs)were prepared by copper mold suction casting method.Their glass forming ability and physical and chemical properties were systematically investigated.The glass forming ability is firstly improved with increasing x,and then decreased when x exceeds 0.44 at.%.Both glass transition temperature and crystallization temperature are increased,while the supercooled liquid region is narrowed,with Fe−C micro-alloying.The hardness,yielding and fracture strength,and plasticity firstly increase and then decrease when x reaches up to 1.32 at.%.The plasticity of the BMG(x=1.32 at.%)is six times that of the Fe-free and C-free BMG.In addition,by the Fe−C micro-alloying,the corrosion potential is slightly decreased,while the corrosion current density increases.The pitting corrosion becomes increasingly serious with the increase of Fe and C content.展开更多
Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface ...Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface modification to obtain the superhydrophobic Febased amorphous coatings with high hardness and dense structure on the Q 235 substrate.The results showed that the water contact angles(WCA)of the superhydrophobic coating was 160°±3.6°,and water droplets could bounce off the superhydrophobic coating surface,illustrating the excellent self-cleaning performance of coating.Notably,the corrosion current density(i_(corr))of the superhydrophobic coating further decreased by 2 orders of magnitude down to8.008×10^(-8)A·cm^(-2)compared to the as-deposited coating with 5.473×10^(-6)A·cm^(-2);the corrosion potential(E_(corr))of the superhydrophobic coating shifted by 34 mV to the positive side compared with that of the as-deposited coating(-310 mV).Likewise,the impedance modulus|Z|values of the superhydrophobic coating increased by nearly2 orders of magnitude up to 1×10^(5.6)compared to the asdeposited coating with 1×10^(3.8).Even through lasting immersion in NaCl for 10 days,|Z|values of the superhydrophobic coating were still much higher than those of the as-deposited coating.The superhydrophobic Fe-based amorphous coatings could respond to their applications under extreme conditions due to their excellent hydrophobicity and self-cleaning properties,illustrating their promising future in aerospace,automotive,and machinery industries.展开更多
Cu60Zr30Ti10 (at. %) ribbon was prepared by melt spinning. Its glassy structure was confirmed by X-ray diffraction (XRD). Its corrosion behavior in HCl and NaCl solutions was investigated by electrochemical polarizati...Cu60Zr30Ti10 (at. %) ribbon was prepared by melt spinning. Its glassy structure was confirmed by X-ray diffraction (XRD). Its corrosion behavior in HCl and NaCl solutions was investigated by electrochemical polarization measurement. The surfaces before and after corrosion were observed with scanning electron microscope (SEM) and analysis was performed using electron dispersive spectroscopy (EDS). The results show that the decrease of current density is due to the formation of a mixture of simple oxides or complex oxidic compounds. In both cases, the corrosion potential decreases with increasing chloride concentration. The passive film forms easier in HCl than in NaCl. In addition, the higher is the chloride concentration, the easier is the passivation.展开更多
基金supported by the Science Foundation of Hunan Province,China(No.2020JJ5215)Scientific Research Project of Hunan Provincial Department of Education,China(No.21B0594)the Open Fund of Hunan Key Laboratory of Electromagnetic Equipment Design and Manufacturing,China(No.DC202007)。
文摘Non-isothermal aging(NIA)is a composite heat treatment process that involves heating aging,cooling aging,and complex solute precipitation sequences.The precipitation behavior and the strengthening and toughening mechanisms of the 2014 Al alloy during NIA were studied by employing tensile,fatigue crack growth,hardness,and electronic conductivity tests,as well as high-resolution transmission electron microscopy and scanning electron microscopy.The results show that during NIA,theθ′phase exhibits a complex process of nucleation,nucleation and growth,nucleation and growth and coarsening,growth and coarsening,nucleation and growth,and nucleation.NIA treatment imparts a mixed precipitation characteristic on the alloy,which is manifested as coherent precipitates,including GP zones,θ′′phases,small-sizedθ′phases,and semi-coherent or non-coherent precipitates such as large-sizedθ′phases and equilibriumθphases.The simultaneous strengthening and toughening of the NIA-treated 2014 Al alloy is caused by the synergistic effects of the particle-shearing mechanism and Orowan bypassing mechanism.
基金This work was supported by the National Natural Science Foundation of China(No.51871234)the National Key Research and Development Program of China(No.2016YFB-0300500)the Open Fund of Key Laboratory of Materials Preparation and Protection for Harsh Environment(Nanjing University of Aeronautics and Astronautics),China,and Ministry of Industry and Information Technology,China(No.XCA19013-04).
文摘(Zr_(53)Al_(11.6)Ni_(11.7)Cu_(23.7))_(1−x)(Fe_(77.1)C_(22.9))_(x)(x=0−2.2,at.%)bulk metallic glasses(BMGs)were prepared by copper mold suction casting method.Their glass forming ability and physical and chemical properties were systematically investigated.The glass forming ability is firstly improved with increasing x,and then decreased when x exceeds 0.44 at.%.Both glass transition temperature and crystallization temperature are increased,while the supercooled liquid region is narrowed,with Fe−C micro-alloying.The hardness,yielding and fracture strength,and plasticity firstly increase and then decrease when x reaches up to 1.32 at.%.The plasticity of the BMG(x=1.32 at.%)is six times that of the Fe-free and C-free BMG.In addition,by the Fe−C micro-alloying,the corrosion potential is slightly decreased,while the corrosion current density increases.The pitting corrosion becomes increasingly serious with the increase of Fe and C content.
基金financially supported by the National Natural Science Foundation of China(Nos.51901092,52075234)the Program of"Science and Technology International Cooperation Demonstrative Base of Metal Surface Engineering along the Silk Road(No.2017D01003)"+3 种基金the"111"project(No.D21032)the Key Research Program of Education Department of Gansu Province(No.GSSYLXM-03)the Natural Science Foundation of Gansu Province(No.20JR5RA431)Hongliu Distinguished Young Talent Support Program of Lanzhou University of Technology,and the Open Fund Project of Hunan Province Key Laboratory of Electromagnetic Equipment Design and Manufacturing,Hunan Institute of Technology(No.DC202001)。
文摘Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface modification to obtain the superhydrophobic Febased amorphous coatings with high hardness and dense structure on the Q 235 substrate.The results showed that the water contact angles(WCA)of the superhydrophobic coating was 160°±3.6°,and water droplets could bounce off the superhydrophobic coating surface,illustrating the excellent self-cleaning performance of coating.Notably,the corrosion current density(i_(corr))of the superhydrophobic coating further decreased by 2 orders of magnitude down to8.008×10^(-8)A·cm^(-2)compared to the as-deposited coating with 5.473×10^(-6)A·cm^(-2);the corrosion potential(E_(corr))of the superhydrophobic coating shifted by 34 mV to the positive side compared with that of the as-deposited coating(-310 mV).Likewise,the impedance modulus|Z|values of the superhydrophobic coating increased by nearly2 orders of magnitude up to 1×10^(5.6)compared to the asdeposited coating with 1×10^(3.8).Even through lasting immersion in NaCl for 10 days,|Z|values of the superhydrophobic coating were still much higher than those of the as-deposited coating.The superhydrophobic Fe-based amorphous coatings could respond to their applications under extreme conditions due to their excellent hydrophobicity and self-cleaning properties,illustrating their promising future in aerospace,automotive,and machinery industries.
文摘Cu60Zr30Ti10 (at. %) ribbon was prepared by melt spinning. Its glassy structure was confirmed by X-ray diffraction (XRD). Its corrosion behavior in HCl and NaCl solutions was investigated by electrochemical polarization measurement. The surfaces before and after corrosion were observed with scanning electron microscope (SEM) and analysis was performed using electron dispersive spectroscopy (EDS). The results show that the decrease of current density is due to the formation of a mixture of simple oxides or complex oxidic compounds. In both cases, the corrosion potential decreases with increasing chloride concentration. The passive film forms easier in HCl than in NaCl. In addition, the higher is the chloride concentration, the easier is the passivation.
