The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains...The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains of SGY2 alloy exhibited a pronounced basal plane texture,specifically<01.10>//ED,while the texture of DRXed grains was relatively dispersed.Under the condition of 420℃ and an extrusion ratio of 9.4(420℃-ER9.4),the basal plane texture intensity of unDRXed grains in SGY2 alloy was the highest.Furthermore,SGY2 alloy at different extrusion parameters exhibited recrystallization mechanisms mainly characterized by continuous dynamic recrystallization(CDRX),with some DRXed grains and deformed grains experiencing discontinuous dynamic recrystallization(DDRX).Additionally,at the 420℃-ER9.4,the second phase particles in the as-extruded SGY2 alloy were smaller in size and exhibited a dispersed distribution.Under this condition,a significant amount of dislocation accumulation,dislocation bypassing,and dislocation tangling phenomena were observed in the SGY2 alloy.The primary deformation mechanism of unDRXed grains in the SGY2 alloy at the 420℃-ER9.4 may involve prismatic plane,pyramidal plane,and pyramidal plane<c+a>slip,thereby activating a significant amount of dislocations.Compared to other extrusion conditions,this condition is more prone to activate non-basal plane slip.The as-extruded SGY2 alloy exhibited superior mechanical properties,with ultimate tensile strength(UTS)and yield strength(YS)of 332 MPa and 278 MPa,respectively.This is mainly attributed to the extremely fine grains,with many DRXed grains having grain sizes smaller than 1μm,and higher density grain boundaries produced under this condition.Additionally,the unDRXed grains contain a high density of dislocations with small Schmid factor(SF),thus effectively inhibiting basal plane slip and strengthening the alloy to some extent.Similarly,the increased presence of second phase particles will also contribute to strengthening the alloy matrix through precipitation hardening.展开更多
One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stabi...One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52371108,52201119)Frontier Exploration Project of Longmen Laboratory,China(LMQYTSKT014).
文摘The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains of SGY2 alloy exhibited a pronounced basal plane texture,specifically<01.10>//ED,while the texture of DRXed grains was relatively dispersed.Under the condition of 420℃ and an extrusion ratio of 9.4(420℃-ER9.4),the basal plane texture intensity of unDRXed grains in SGY2 alloy was the highest.Furthermore,SGY2 alloy at different extrusion parameters exhibited recrystallization mechanisms mainly characterized by continuous dynamic recrystallization(CDRX),with some DRXed grains and deformed grains experiencing discontinuous dynamic recrystallization(DDRX).Additionally,at the 420℃-ER9.4,the second phase particles in the as-extruded SGY2 alloy were smaller in size and exhibited a dispersed distribution.Under this condition,a significant amount of dislocation accumulation,dislocation bypassing,and dislocation tangling phenomena were observed in the SGY2 alloy.The primary deformation mechanism of unDRXed grains in the SGY2 alloy at the 420℃-ER9.4 may involve prismatic plane,pyramidal plane,and pyramidal plane<c+a>slip,thereby activating a significant amount of dislocations.Compared to other extrusion conditions,this condition is more prone to activate non-basal plane slip.The as-extruded SGY2 alloy exhibited superior mechanical properties,with ultimate tensile strength(UTS)and yield strength(YS)of 332 MPa and 278 MPa,respectively.This is mainly attributed to the extremely fine grains,with many DRXed grains having grain sizes smaller than 1μm,and higher density grain boundaries produced under this condition.Additionally,the unDRXed grains contain a high density of dislocations with small Schmid factor(SF),thus effectively inhibiting basal plane slip and strengthening the alloy to some extent.Similarly,the increased presence of second phase particles will also contribute to strengthening the alloy matrix through precipitation hardening.
基金financially supported by the National Natural Science Foundation of China(Nos.52164029,52074099 and 52464033)Natural Science Foundation of Hainan Province(Nos.221RC585,821MS0782,221MS048 and 221RC 1072)+1 种基金Hainan Province Science and Technology Special Fund(Nos.ZDYF2022GXJS004 and ZDYF2021GXJS028)Scientific Research Foundation of Hainan Tropical Ocean University(No.RHDRC202112)
文摘One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.
