The stress corrosion cracking(SCC)behaviors of 2A12 aluminum alloy after annealing treatment were studied by slow strain rate testing(SSRT),electrochemical polarization measurement,scanning electron microscope(SEM),en...The stress corrosion cracking(SCC)behaviors of 2A12 aluminum alloy after annealing treatment were studied by slow strain rate testing(SSRT),electrochemical polarization measurement,scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and transmission electron microscopy(TEM).Various concentrations of NaCl,H_(2)SO_(4)and HCl aqueous solution were prepared to act as the corrosive solution.The experimental results show that regarding the SCC,2A12 alloy performs best in NaCl solution but worst in HCl solution and intermediately between the above mentioned two cases in H_(2)SO_(4)solution.For the SSRT carried out in room temperature,there is a higher decrease in elongation without large strength loss for the alloy immersed in NaCl solution.With the test conducted in H_(2)SO_(4)solution,there is a higher strength loss and a relatively less loss of elongation compared to the one immersed in NaCl solution.With the test conducted in HCl solution,there is a relativel level loss of strength and elongation compared to either result carried out in NaCl solution or H_(2)SO_(4)solution.展开更多
In marine environments,the durability of reinforced concrete structures such as bridges,which suffer from the coupled effects of corrosion and fatigue damage,is significantly reduced.Fatigue loading can result in seve...In marine environments,the durability of reinforced concrete structures such as bridges,which suffer from the coupled effects of corrosion and fatigue damage,is significantly reduced.Fatigue loading can result in severe dete-rioration of the bonds between reinforcing steel bars and the surrounding concrete,particularly when reinforcing bars are corroded.Uniaxial tension testing was conducted under static loading and fatigue loading conditions to investigate the bonding characteristics between corroded reinforcing bars and concrete.An electrolyte corrosion technique was used to accelerate steel corrosion.The results show that the bond strength was reduced under fati-gue loading,although the concrete did not crack.Therefore,fatigue loading has negative effects on the bond strength between corroded steel bars and concrete.The effects of corrosion cracking on bond strength become more pronounced after corrosion cracking appears along the main reinforcing bars.When the average width of cracking along main reinforcing bars exceeds 3 mm,the bonding properties deteriorate rapidly based on the effects of corrosion cracking,whereas fatigue loading exhibits no additional effects on bond strength.展开更多
To effectively alleviate the surface structure degradation caused by electrolyte corrosion and transition metal(TM) dissolution for Ni-rich(Ni content > 0.6) cathode materials, porous Zirconium based metalorganic f...To effectively alleviate the surface structure degradation caused by electrolyte corrosion and transition metal(TM) dissolution for Ni-rich(Ni content > 0.6) cathode materials, porous Zirconium based metalorganic frameworks(Zr-MOFs, UiO-66) material is utilized herein as a positive electrode additive. UiO-66 owns tunable attachment sites and strong binding affinity, making itself an efficient defluorination agent to suppress the undesirable reactions caused by fluorine species. Besides, it can also relieve TMs dissolution and block the migration of TMs toward anode side since it’s a multifarious metal ions adsorbent,realizing both cathode and anode interface protection. Benefiting from these advantages, the UiO-66 assistant Ni-rich cathode achieves superior cycling stability. Particularly in full cell, the positive effects of this multifunctional additive are more pronounced than in the half-cell, that is after 400 cycles at 2 C,the capacity retention has doubled with the addition of UiO-66. More broadly, this unique application of functional additive provides new insight into the degradation mechanism of layered cathode materials and offers a new avenue to develop high-energy density batteries.展开更多
基金Funded by the National Project of Manufacturing and Application Technology of High-performance and Large-size Extruding of Aluminum Alloy(No.2016YFB0300901)。
文摘The stress corrosion cracking(SCC)behaviors of 2A12 aluminum alloy after annealing treatment were studied by slow strain rate testing(SSRT),electrochemical polarization measurement,scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and transmission electron microscopy(TEM).Various concentrations of NaCl,H_(2)SO_(4)and HCl aqueous solution were prepared to act as the corrosive solution.The experimental results show that regarding the SCC,2A12 alloy performs best in NaCl solution but worst in HCl solution and intermediately between the above mentioned two cases in H_(2)SO_(4)solution.For the SSRT carried out in room temperature,there is a higher decrease in elongation without large strength loss for the alloy immersed in NaCl solution.With the test conducted in H_(2)SO_(4)solution,there is a higher strength loss and a relatively less loss of elongation compared to the one immersed in NaCl solution.With the test conducted in HCl solution,there is a relativel level loss of strength and elongation compared to either result carried out in NaCl solution or H_(2)SO_(4)solution.
基金This work was supported by the Fundamental Research Funds for Beijing Universities(110052971921/059).S H received the Grant。
文摘In marine environments,the durability of reinforced concrete structures such as bridges,which suffer from the coupled effects of corrosion and fatigue damage,is significantly reduced.Fatigue loading can result in severe dete-rioration of the bonds between reinforcing steel bars and the surrounding concrete,particularly when reinforcing bars are corroded.Uniaxial tension testing was conducted under static loading and fatigue loading conditions to investigate the bonding characteristics between corroded reinforcing bars and concrete.An electrolyte corrosion technique was used to accelerate steel corrosion.The results show that the bond strength was reduced under fati-gue loading,although the concrete did not crack.Therefore,fatigue loading has negative effects on the bond strength between corroded steel bars and concrete.The effects of corrosion cracking on bond strength become more pronounced after corrosion cracking appears along the main reinforcing bars.When the average width of cracking along main reinforcing bars exceeds 3 mm,the bonding properties deteriorate rapidly based on the effects of corrosion cracking,whereas fatigue loading exhibits no additional effects on bond strength.
基金National Key R&D Program of China(2016YFB0100301)the National Natural Science Foundation of China(21875022,51802020,U1664255)+1 种基金Beijing Institute of Technology Research Fund Program for Young ScholarsYoung Elite Scientists Sponsorship Program by CAST(2018QNRC001)。
文摘To effectively alleviate the surface structure degradation caused by electrolyte corrosion and transition metal(TM) dissolution for Ni-rich(Ni content > 0.6) cathode materials, porous Zirconium based metalorganic frameworks(Zr-MOFs, UiO-66) material is utilized herein as a positive electrode additive. UiO-66 owns tunable attachment sites and strong binding affinity, making itself an efficient defluorination agent to suppress the undesirable reactions caused by fluorine species. Besides, it can also relieve TMs dissolution and block the migration of TMs toward anode side since it’s a multifarious metal ions adsorbent,realizing both cathode and anode interface protection. Benefiting from these advantages, the UiO-66 assistant Ni-rich cathode achieves superior cycling stability. Particularly in full cell, the positive effects of this multifunctional additive are more pronounced than in the half-cell, that is after 400 cycles at 2 C,the capacity retention has doubled with the addition of UiO-66. More broadly, this unique application of functional additive provides new insight into the degradation mechanism of layered cathode materials and offers a new avenue to develop high-energy density batteries.