High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonethele...High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonetheless,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto reported.Most interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing solutions.Through extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.展开更多
The dynamic mechanical relaxation behavior of Ti36.2Zr30.3Cu8.3Fe4Be21.2 bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy.The mechanical relaxation behavior was analyzed ...The dynamic mechanical relaxation behavior of Ti36.2Zr30.3Cu8.3Fe4Be21.2 bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy.The mechanical relaxation behavior was analyzed in the framework of quasi-point defects model.The experimental results demonstrate that the atomic mobility of the metallic glass is closely associated with the correlation factorχ.The physical aging below the glass transition temperature T g shows a non-Debye relaxation behavior,which could be well described by stretched Kohlrausch exponential equation.The Kohlrausch exponentβaging reflects the dynamic heterogeneities of the metallic glass.Both concentration of"defects"and atomic mobility decrease caused by the in situ successive heating during the mechanical spectroscopy experiments.展开更多
基金Y.Yang was supported by Research Grant Council(RGC),Hong Kong Government,through General Research Fund(RGC)(Nos.CityU11213118,CityU11200719 and CityU11209317).
文摘High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonetheless,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto reported.Most interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing solutions.Through extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.
基金supported by the National Natural Science Foundation of China (Nos. 51611130120, 11772257, 11572249, 51871132)supported by the Fundamental Research Funds for the Central Universities (Nos. 3102018ZY010, 3102017HQZZ012)
文摘The dynamic mechanical relaxation behavior of Ti36.2Zr30.3Cu8.3Fe4Be21.2 bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy.The mechanical relaxation behavior was analyzed in the framework of quasi-point defects model.The experimental results demonstrate that the atomic mobility of the metallic glass is closely associated with the correlation factorχ.The physical aging below the glass transition temperature T g shows a non-Debye relaxation behavior,which could be well described by stretched Kohlrausch exponential equation.The Kohlrausch exponentβaging reflects the dynamic heterogeneities of the metallic glass.Both concentration of"defects"and atomic mobility decrease caused by the in situ successive heating during the mechanical spectroscopy experiments.
