With the aim of improving corrosion resistance of rod cladding for in-service and accident conditions,six new zirconium alloys(named N1-N6)have been designed.The contents of Sn and Nb were optimized for better behavio...With the aim of improving corrosion resistance of rod cladding for in-service and accident conditions,six new zirconium alloys(named N1-N6)have been designed.The contents of Sn and Nb were optimized for better behavior at high-temperature pressurized water,and Fe,Cr,V,Cu or Mo elements were added to the alloys to adjust the corrosion behavioi\The current work focused on the rapid corrosion behavior in 500℃/10.3 MPa steam for up to 1960 h,aiming to test the corrosion resistance at high temperature.The structure of matrix and properties of second-phase particles(SPPs)were characterized to find the main differences among these alloys.All the six alloys exhibited better corrosion resistance than N36,and NI was shown to have the best performance.A careful analysis of the corrosion kinetics curves revealed that Cr was beneficial for severe condition.Elements Fe,Cr,V,Cu or Mo aggregated into SPPs with diiferent concentrations and structures.This was demonstrated to be the main reason for different corrosion resistance.Due to good processing control,all alloys had a uniform structure and a uniform distribution of SPPs.As for N4,N6 and N36,the existing of large-size SPPs(450 nm)might be a contributing factor of the relatively poor corrosion resistance.展开更多
The hot deformation behavior of FeCrAl-ODS alloys at temperatures of 1050-1200℃ and strain rates of 0.001-1 s^(-1),investigated.The peak stress of FeCrAl-ODS alloy during hot deformation decreased with increasing tem...The hot deformation behavior of FeCrAl-ODS alloys at temperatures of 1050-1200℃ and strain rates of 0.001-1 s^(-1),investigated.The peak stress of FeCrAl-ODS alloy during hot deformation decreased with increasing temperature and decreasing strain rate.In addition,the stress-strain curves show a dynamic softening phenomenon according to the shape of the flow curves.Based on the Arrhenius-type model,a constitutive equation and processing map of FeCrAl-ODS alloy were established.Thereafter,we proposed optimum processing parameters of 1200℃ and 0.001 s^(-1)based on the processing map.Compared with FeCrAl alloys,there was no significant phenomenon of grain coarsening during hot deformation in FeCrAl-ODS alloy.In the electron backscattered diffraction images,both recrystallized and recovered grains were observed in the matrix under dfferent deformation conditions.The fraction of dynamically recrystallized grains in the matrix under the deformation of 1100 C/0.001 s^(-1)(42.5%)was significantly higher than that at 1200℃/0.001 s^(-1)(10.6%),which was consistent with the stress-strain curves.展开更多
基金funded by the Major Project of CNNC (China National Nuclear Corporation): Key Technology Research on CF4 Fuel Assembly and Associated Assembly (No.[2016] 298)
文摘With the aim of improving corrosion resistance of rod cladding for in-service and accident conditions,six new zirconium alloys(named N1-N6)have been designed.The contents of Sn and Nb were optimized for better behavior at high-temperature pressurized water,and Fe,Cr,V,Cu or Mo elements were added to the alloys to adjust the corrosion behavioi\The current work focused on the rapid corrosion behavior in 500℃/10.3 MPa steam for up to 1960 h,aiming to test the corrosion resistance at high temperature.The structure of matrix and properties of second-phase particles(SPPs)were characterized to find the main differences among these alloys.All the six alloys exhibited better corrosion resistance than N36,and NI was shown to have the best performance.A careful analysis of the corrosion kinetics curves revealed that Cr was beneficial for severe condition.Elements Fe,Cr,V,Cu or Mo aggregated into SPPs with diiferent concentrations and structures.This was demonstrated to be the main reason for different corrosion resistance.Due to good processing control,all alloys had a uniform structure and a uniform distribution of SPPs.As for N4,N6 and N36,the existing of large-size SPPs(450 nm)might be a contributing factor of the relatively poor corrosion resistance.
基金supported by Scientific Research Program for Young Talent of China National Nuclear Corporation(No.NPIC-K301007003)。
文摘The hot deformation behavior of FeCrAl-ODS alloys at temperatures of 1050-1200℃ and strain rates of 0.001-1 s^(-1),investigated.The peak stress of FeCrAl-ODS alloy during hot deformation decreased with increasing temperature and decreasing strain rate.In addition,the stress-strain curves show a dynamic softening phenomenon according to the shape of the flow curves.Based on the Arrhenius-type model,a constitutive equation and processing map of FeCrAl-ODS alloy were established.Thereafter,we proposed optimum processing parameters of 1200℃ and 0.001 s^(-1)based on the processing map.Compared with FeCrAl alloys,there was no significant phenomenon of grain coarsening during hot deformation in FeCrAl-ODS alloy.In the electron backscattered diffraction images,both recrystallized and recovered grains were observed in the matrix under dfferent deformation conditions.The fraction of dynamically recrystallized grains in the matrix under the deformation of 1100 C/0.001 s^(-1)(42.5%)was significantly higher than that at 1200℃/0.001 s^(-1)(10.6%),which was consistent with the stress-strain curves.
