The cooling rate during vitrification is critical for determining the mechanical properties of metallic glasses.However,the structural origin of the cooling rate effect on mechanical behaviors is unclear.In this work,...The cooling rate during vitrification is critical for determining the mechanical properties of metallic glasses.However,the structural origin of the cooling rate effect on mechanical behaviors is unclear.In this work,a systematical investigation of the cooling rate effect on the deformation mode,shear band nucleation,and nanoscale heterogeneous structure was conducted in three Fe-based metallic glasses.The brittle to ductile deformation transition was observed when increasing the cooling rate.Meanwhile,the governing shear band nucleation site from high load site to low load site appears the synchronous tran-sition.By studying the corresponding nanoscale heterogeneous structure,it was found that nanoscale viscoelastic transition from solid-like to liquid-like as increasing cooling rate enables ductile deformation.The current work not only reveals the nanoscale structural origin of the cooling rate effect on the de-formation behaviors,but also provides a new route to design ductile metallic glasses by freezing more nanoscale liquid-like regions during cooling.展开更多
The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The...The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The composite S5 obtained from an optimized mass ratio(5%) of CeVO_4 to dicyanamide(DCDA) exhibits the highest photocatalytic activity. Here, ternary Ag/CeVO_4/g-C_3N_4 composites denoted as X%Ag/S5 were prepared by an ultrasonic precipitation method to improve the photocatalytic property of S5. The TEM images show that CeVO_4 and Ag nanoparticles are well distributed on the layered g-C_3N_4, which agree well with the XRD results. The UV spectra show that the 7%Ag/S5 sample has the widest absorption range and the enhanced absorption intensity under visible light irradiation. The corresponding band gap of 7%Ag/S5(2.5 eV) is much lower than that of S5(2.65 eV). The corresponding k value of 7%Ag/S5 is much higher than those of g-C_3N_4 and CeVO_4. The degradation experiments for MB solution suggest that the 7%Ag/S5 sample has the optimal photocatalytic performance, which can degrade MB solution completely within 120 min. The enhanced photocatalytic property of the composites is ascribed to not only the effect of heterojunction structure, but also the surface plasma resonance effect of Ag nanoparticles.展开更多
基金supported by the National Natural Science Foun-dation of China(Nos.52201194,52222105,52261028,52001269,92163108,52231006)the 3315 Innovation Youth Talent in Ningbo City(No.2021A123G)+3 种基金the Youth Innovation Promotion Association CAS(No.2019296)the Zhejiang Provincial Natural Science Foun-dation of China(No.LR22E010004)the Zhejiang Provincial Natu-ral Science Foundation Regional Innovation and Development Joint Foundation with Quzhou City(No.LZY23E010002)the Nat-ural Science Foundation of Xinjiang Uygur Autonomous Region of China(No.2022D01C383).
文摘The cooling rate during vitrification is critical for determining the mechanical properties of metallic glasses.However,the structural origin of the cooling rate effect on mechanical behaviors is unclear.In this work,a systematical investigation of the cooling rate effect on the deformation mode,shear band nucleation,and nanoscale heterogeneous structure was conducted in three Fe-based metallic glasses.The brittle to ductile deformation transition was observed when increasing the cooling rate.Meanwhile,the governing shear band nucleation site from high load site to low load site appears the synchronous tran-sition.By studying the corresponding nanoscale heterogeneous structure,it was found that nanoscale viscoelastic transition from solid-like to liquid-like as increasing cooling rate enables ductile deformation.The current work not only reveals the nanoscale structural origin of the cooling rate effect on the de-formation behaviors,but also provides a new route to design ductile metallic glasses by freezing more nanoscale liquid-like regions during cooling.
基金supported by National Natural Science Foundation of China(No.51502116)the Six Talents Peak Project in Jiangsu Province(No.2011-ZBZZ045)+2 种基金Natural Science Foundation of Jiangsu Province(No.BK20140557)Special Funding of China Postdoctoral Science Foundation(No.2016T90425)China Postdoctoral Science Foundation(No.2015M571682)
文摘The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The composite S5 obtained from an optimized mass ratio(5%) of CeVO_4 to dicyanamide(DCDA) exhibits the highest photocatalytic activity. Here, ternary Ag/CeVO_4/g-C_3N_4 composites denoted as X%Ag/S5 were prepared by an ultrasonic precipitation method to improve the photocatalytic property of S5. The TEM images show that CeVO_4 and Ag nanoparticles are well distributed on the layered g-C_3N_4, which agree well with the XRD results. The UV spectra show that the 7%Ag/S5 sample has the widest absorption range and the enhanced absorption intensity under visible light irradiation. The corresponding band gap of 7%Ag/S5(2.5 eV) is much lower than that of S5(2.65 eV). The corresponding k value of 7%Ag/S5 is much higher than those of g-C_3N_4 and CeVO_4. The degradation experiments for MB solution suggest that the 7%Ag/S5 sample has the optimal photocatalytic performance, which can degrade MB solution completely within 120 min. The enhanced photocatalytic property of the composites is ascribed to not only the effect of heterojunction structure, but also the surface plasma resonance effect of Ag nanoparticles.
