Bidirectional electromigration rehabilitation(BIEM)is a novel electrochemical rehabilitation method involving the injection of inhibitors into steel bar surface.The BIEM effect and hydrogen embrittlement(HE)risk depen...Bidirectional electromigration rehabilitation(BIEM)is a novel electrochemical rehabilitation method involving the injection of inhibitors into steel bar surface.The BIEM effect and hydrogen embrittlement(HE)risk depend on the electrochemical parameters(current density and duration)and operating condition(stress level and concrete cover thickness)of reinforced concrete structures.Experiments were performed in this study to investigate the relationships between the aforementioned factors.For a small current density group,a linear relationship was established between electric flux and chloride extraction.For a large current density group,the reasonable current density,stress level,and treatment time were obtained.Finally,the querying method of electrochemical parameters combined with treatment time and current density was proposed.展开更多
In this paper,the effect of cathodic polarization on corrosion behavior of AA7003 under three kinds of aging treatments(including peak aging(PA),double peak aging(DPA)and regression re-aging(RRA))was studied in 3.5 wt...In this paper,the effect of cathodic polarization on corrosion behavior of AA7003 under three kinds of aging treatments(including peak aging(PA),double peak aging(DPA)and regression re-aging(RRA))was studied in 3.5 wt%sodium chloride solution through slow strain rate testing(SSRT)and electrochemical testing.X-ray diffraction(XRD)and scanning electron microscopy(SEM)methods were also applied to investigating corrosion behavior and fracture morphology.The results showed that under open circuit,stress corrosion cracking(SCC)of AA7003 might by classified as anodic dissolution.In this case,the extent of SCC susceptibility(ISCC)of AA7003 alloy with different aging treatments was as follows:ISCC(PA)>ISCC(DPA)>ISCC(RRA).On the other hand,stress corrosion cracking(SCC)of AA7003 under cathodic polarization might be classified as hydrogen embrittlement(HE)which had been proved in this paper by presence of AlH3 diffraction peak in XRD patterns.In this case,for AA7003 with any of the three aging treatments,hydrogen embrittlement susceptibility(IHE)increases with negatively shifting of cathodic polarization.展开更多
With no annealing treatment, cathodic polarization trends in 5083F A1 alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion pr...With no annealing treatment, cathodic polarization trends in 5083F A1 alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion protection potential compared to the non-annealed specimen. The results of SSRTs conducted in seawater at the applied potential range of-l.8 V to -0.5 V indicated that the maximum tensile strength, elongation, and time-to-fracture had high values at applied potentials of -0.7 to -1.4 V. The maximum tensile strength, elongation, and time-to-f？acture decreased when the potential values were beyond this range in either anodic or cathodic direction. In general, the increased shear lip caused by annealing treatment indicates elongation. Time-to-fracture would likely increase with elongation. Potentials between -0.5 V to -0.6 V were found to be in the region of stress corrosion cracking. The corrosion protection zone was determined to be -0.7 V to -J,4 V because these potential ranges produced good mechanical properties. Potential less than -1.4 V produced a fractured surface with a mixture of dimples （ductile fractures） and a quasi-cleavage pattern resulting from the effects of hydrogen gas.展开更多
基金Projects(51908496,51878610,51820105012,51778577,51638013)supported by the National Natural Science Foundation of ChinaProjects(LY18E080003,LQ19E080011,LQ19E080012,LQ20E080001)supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(2018A610359)supported by the Natural Science Foundation of Ningbo,China。
文摘Bidirectional electromigration rehabilitation(BIEM)is a novel electrochemical rehabilitation method involving the injection of inhibitors into steel bar surface.The BIEM effect and hydrogen embrittlement(HE)risk depend on the electrochemical parameters(current density and duration)and operating condition(stress level and concrete cover thickness)of reinforced concrete structures.Experiments were performed in this study to investigate the relationships between the aforementioned factors.For a small current density group,a linear relationship was established between electric flux and chloride extraction.For a large current density group,the reasonable current density,stress level,and treatment time were obtained.Finally,the querying method of electrochemical parameters combined with treatment time and current density was proposed.
基金Projects(51371039,51871031)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘In this paper,the effect of cathodic polarization on corrosion behavior of AA7003 under three kinds of aging treatments(including peak aging(PA),double peak aging(DPA)and regression re-aging(RRA))was studied in 3.5 wt%sodium chloride solution through slow strain rate testing(SSRT)and electrochemical testing.X-ray diffraction(XRD)and scanning electron microscopy(SEM)methods were also applied to investigating corrosion behavior and fracture morphology.The results showed that under open circuit,stress corrosion cracking(SCC)of AA7003 might by classified as anodic dissolution.In this case,the extent of SCC susceptibility(ISCC)of AA7003 alloy with different aging treatments was as follows:ISCC(PA)>ISCC(DPA)>ISCC(RRA).On the other hand,stress corrosion cracking(SCC)of AA7003 under cathodic polarization might be classified as hydrogen embrittlement(HE)which had been proved in this paper by presence of AlH3 diffraction peak in XRD patterns.In this case,for AA7003 with any of the three aging treatments,hydrogen embrittlement susceptibility(IHE)increases with negatively shifting of cathodic polarization.
文摘With no annealing treatment, cathodic polarization trends in 5083F A1 alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion protection potential compared to the non-annealed specimen. The results of SSRTs conducted in seawater at the applied potential range of-l.8 V to -0.5 V indicated that the maximum tensile strength, elongation, and time-to-fracture had high values at applied potentials of -0.7 to -1.4 V. The maximum tensile strength, elongation, and time-to-f？acture decreased when the potential values were beyond this range in either anodic or cathodic direction. In general, the increased shear lip caused by annealing treatment indicates elongation. Time-to-fracture would likely increase with elongation. Potentials between -0.5 V to -0.6 V were found to be in the region of stress corrosion cracking. The corrosion protection zone was determined to be -0.7 V to -J,4 V because these potential ranges produced good mechanical properties. Potential less than -1.4 V produced a fractured surface with a mixture of dimples （ductile fractures） and a quasi-cleavage pattern resulting from the effects of hydrogen gas.
