In the application of WE43,it is found that Y_(2)O_(3)inclusion formed in the process of casting seriously reduced the mechanical properties of the products.The reduction of the mechanical properties is even more dist...In the application of WE43,it is found that Y_(2)O_(3)inclusion formed in the process of casting seriously reduced the mechanical properties of the products.The reduction of the mechanical properties is even more distinct when it comes to the application in the thin walled complex-precision castings.In order to decrease the Y_(2)O_(3)inclusions,Gd element was used to replace part of the Y element in Mg-Y-RE series alloys.The effect of Y content(Mg-x Y-1Gd-2Nd-0.5Zn-0.5Zr)and Y/Gd ratio(Mg-x Y-(5-x)Gd-2Nd-0.5Zn-0.5Zr)on the microstructure and mechanical properties of Mg-Y-RE alloys were investigated in this paper.With decreasing Y content,the grain size of the alloys increased,both ultimate tensile strength(UTS)and yield strength(YS)of alloys decreased monotonically.Replacing part of Y content with Gd and keeping the total rare earth content unchanged,the low Y content Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy showed the same mechanical properties as the high Y content Mg-4Y-1Gd-2Nd-0.5Zn-0.5Zr alloy at both room and elevated temperatures.After solution treatment at 525°C for 8 h and aging treatment at 225°C for 10 h,the UTS,YS and elongation(ε)of Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy reached 281.7 MPa,198 MPa and 11.1%at room temperature,and 216.7 MPa,171.6 MPa and 16.1%at 250°C.The new low Y content Mg-2Y-2Nd-3Gd-0.5Zn-0.5Zr alloy is expected to replace the high Y content WE43 alloys,which can be used in the complex thin-walled parts of aviation products.展开更多
The effects of different proportions of La and Y elements in the A-side on the structure and properties of A_(2)B_(7)-type La-Y-Ni hydrogen storage alloys were investigated.The(La,Y)_(2)Ni_(7)hydrogen storage alloys w...The effects of different proportions of La and Y elements in the A-side on the structure and properties of A_(2)B_(7)-type La-Y-Ni hydrogen storage alloys were investigated.The(La,Y)_(2)Ni_(7)hydrogen storage alloys with different La/Y ratios were prepared by sintering the Y_(2)Ni_(4)precursor and different AB_(5)-type precursors at 1298 K for 5 h and subsequently annealed for 20 h at 1248 K.All the alloys only contain Ce_(2)Ni_(7)(2H-type)and Gd_(2)Co_(7)(3R-type)phases with different mass ratios.As the La/Y ratio decreases,the cell volume of the two phases declines and the corresponding plateau pressure gradually increases.As the proportion of Y in the alloy increases,the hydrogen storage capacity increases gradually from 1.309 wt%(La/Y=1/1)to 1.713 wt%(La/Y=1/5)and the high-rate discharge(HRD1500)ability of the alloy electrodes increases gradually from 62.7%(La/Y=1/1)to 88.6%(La/Y=1/5).The hydrogen diffusion rate in the bulk of the alloy is the controlling step of hydriding/dehydriding kinetics.The Y ele ment can effectively inhibit the hydrogen-induced amorphous(HIA)of La-Y-Ni alloys,but the poor stability of the Y element in alkaline KOH aqueous solution leads to a decrease in the electrochemical cyclic stability with increasing Y content.展开更多
Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There i...Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There is a higher yellow light/blue light(Y/B)value,indicating an increase in the covalentity of Dy-O,and decrease in the symmetry with the increasing concentration of dopants(Dy^3+).The correlated color temperature(CCT)can be effectively reduced by the red light emission of Eu^3+,and the order of influence of excitation wavelength on CCT is 395 nm>382 nm>365 nm.The delay curve demonstrates the energy transfer from Dy^3+to Eu^3+.The glass has the characteristics of anti-blue light damage and wide tunable color temperature,which illustrates that it has potential application in the field of white LED.展开更多
The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigat...The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigated Mg–Y–Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios.Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates,but also leads to the precipitation of Mg_(24)Y_(5) phase.The corrosion rate of Mg–Y–Zn based alloys greatly increases from 7.4 mg·cm^(−2)·day^(−1) to 11.3 mg·cm^(−2)·day^(−1) with increasing the Y/Zn mole ratio up to 3.It should be attributed to the decreasing size of LPSO phase plates as cathodes,further increasing the hydrogen evolution kinetics.The related corrosion mechanism is discussed in details.展开更多
The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explain...The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explained from the ternary phase diagram calculation. The results show that the formation of the secondary phases in Mg-Zn-Y-Zr alloys firmly depends on the mole ratio of Y to Zn, and X （Mg 12 YZn）-phase, W （Mg 3 Y 2 Zn 3 ）-phase and I （Mg 3 YZn 6 ）-phase come out in sequence as the ratio of Y to Zn decreases. The mole ratios of Y to Zn with the corresponding phase constituent are suggested quantitatively as follows： the phase constituent is α-Mg ＋ I when the mole ratio of Y to Zn is about 0.164; α-Mg ＋ I ＋W when the mole ratio of Y to Zn is in the range of 0.164 0.33;α-Mg ＋W when the mole ratio of Y to Zn is about 0.33; α-Mg ＋W＋X when the mole ratio of Y to Zn is in the range of 0.33 1.32; and α-Mg ＋X when the mole ratio of Y to Zn is about 1.32. The results also offer a guideline for alloy selection and alloy design in Mg-Zn-Y-Zr system.展开更多
基金This work is supported by National Natural Science Foundation of China(No.51775334,51771115)National Key Research and Development Program of China(No.2016YFB0301004)+1 种基金National Science and Technology Ma-jor Project(No.2017ZX04006001)Science Innovation Foundation of Shanghai Academy of Spaceflight Technology(No.SAST2016048).
文摘In the application of WE43,it is found that Y_(2)O_(3)inclusion formed in the process of casting seriously reduced the mechanical properties of the products.The reduction of the mechanical properties is even more distinct when it comes to the application in the thin walled complex-precision castings.In order to decrease the Y_(2)O_(3)inclusions,Gd element was used to replace part of the Y element in Mg-Y-RE series alloys.The effect of Y content(Mg-x Y-1Gd-2Nd-0.5Zn-0.5Zr)and Y/Gd ratio(Mg-x Y-(5-x)Gd-2Nd-0.5Zn-0.5Zr)on the microstructure and mechanical properties of Mg-Y-RE alloys were investigated in this paper.With decreasing Y content,the grain size of the alloys increased,both ultimate tensile strength(UTS)and yield strength(YS)of alloys decreased monotonically.Replacing part of Y content with Gd and keeping the total rare earth content unchanged,the low Y content Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy showed the same mechanical properties as the high Y content Mg-4Y-1Gd-2Nd-0.5Zn-0.5Zr alloy at both room and elevated temperatures.After solution treatment at 525°C for 8 h and aging treatment at 225°C for 10 h,the UTS,YS and elongation(ε)of Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy reached 281.7 MPa,198 MPa and 11.1%at room temperature,and 216.7 MPa,171.6 MPa and 16.1%at 250°C.The new low Y content Mg-2Y-2Nd-3Gd-0.5Zn-0.5Zr alloy is expected to replace the high Y content WE43 alloys,which can be used in the complex thin-walled parts of aviation products.
基金Project supported by the National Natural Science Foundation of China(51961002)National Key Research and Development Projects of China(2018YFE124400)+2 种基金Natural Science Foundation of Inner Mongolia(2020MS05013,2018MS05016)Science and Technology Program of Inner Mongolia(2020B2156)Special Project of Achievement Transformation in Inner Mongolia(2019CG082)。
文摘The effects of different proportions of La and Y elements in the A-side on the structure and properties of A_(2)B_(7)-type La-Y-Ni hydrogen storage alloys were investigated.The(La,Y)_(2)Ni_(7)hydrogen storage alloys with different La/Y ratios were prepared by sintering the Y_(2)Ni_(4)precursor and different AB_(5)-type precursors at 1298 K for 5 h and subsequently annealed for 20 h at 1248 K.All the alloys only contain Ce_(2)Ni_(7)(2H-type)and Gd_(2)Co_(7)(3R-type)phases with different mass ratios.As the La/Y ratio decreases,the cell volume of the two phases declines and the corresponding plateau pressure gradually increases.As the proportion of Y in the alloy increases,the hydrogen storage capacity increases gradually from 1.309 wt%(La/Y=1/1)to 1.713 wt%(La/Y=1/5)and the high-rate discharge(HRD1500)ability of the alloy electrodes increases gradually from 62.7%(La/Y=1/1)to 88.6%(La/Y=1/5).The hydrogen diffusion rate in the bulk of the alloy is the controlling step of hydriding/dehydriding kinetics.The Y ele ment can effectively inhibit the hydrogen-induced amorphous(HIA)of La-Y-Ni alloys,but the poor stability of the Y element in alkaline KOH aqueous solution leads to a decrease in the electrochemical cyclic stability with increasing Y content.
基金Project supported by Science and Technology Department of Jilin Province of China(20190302006GX)Technology Innovation Fund of Changchun University of Science and Technology(XJJLG-2017-06,XJJLG-2018-10)。
文摘Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There is a higher yellow light/blue light(Y/B)value,indicating an increase in the covalentity of Dy-O,and decrease in the symmetry with the increasing concentration of dopants(Dy^3+).The correlated color temperature(CCT)can be effectively reduced by the red light emission of Eu^3+,and the order of influence of excitation wavelength on CCT is 395 nm>382 nm>365 nm.The delay curve demonstrates the energy transfer from Dy^3+to Eu^3+.The glass has the characteristics of anti-blue light damage and wide tunable color temperature,which illustrates that it has potential application in the field of white LED.
文摘The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigated Mg–Y–Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios.Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates,but also leads to the precipitation of Mg_(24)Y_(5) phase.The corrosion rate of Mg–Y–Zn based alloys greatly increases from 7.4 mg·cm^(−2)·day^(−1) to 11.3 mg·cm^(−2)·day^(−1) with increasing the Y/Zn mole ratio up to 3.It should be attributed to the decreasing size of LPSO phase plates as cathodes,further increasing the hydrogen evolution kinetics.The related corrosion mechanism is discussed in details.
基金Project(50725413)supported by the National Natural Science Foundation of China
文摘The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich corner was investigated by XRD and SEM/EDS analysis and was further explained from the ternary phase diagram calculation. The results show that the formation of the secondary phases in Mg-Zn-Y-Zr alloys firmly depends on the mole ratio of Y to Zn, and X （Mg 12 YZn）-phase, W （Mg 3 Y 2 Zn 3 ）-phase and I （Mg 3 YZn 6 ）-phase come out in sequence as the ratio of Y to Zn decreases. The mole ratios of Y to Zn with the corresponding phase constituent are suggested quantitatively as follows： the phase constituent is α-Mg ＋ I when the mole ratio of Y to Zn is about 0.164; α-Mg ＋ I ＋W when the mole ratio of Y to Zn is in the range of 0.164 0.33;α-Mg ＋W when the mole ratio of Y to Zn is about 0.33; α-Mg ＋W＋X when the mole ratio of Y to Zn is in the range of 0.33 1.32; and α-Mg ＋X when the mole ratio of Y to Zn is about 1.32. The results also offer a guideline for alloy selection and alloy design in Mg-Zn-Y-Zr system.
