The microstructure,mechanical properties and flame resistance behavior of the AZ91−1Ce alloys with different Ca additions were firstly investigated.Then,the effect of processing parameters,including applied pressures ...The microstructure,mechanical properties and flame resistance behavior of the AZ91−1Ce alloys with different Ca additions were firstly investigated.Then,the effect of processing parameters,including applied pressures and rotation speeds,on the microstructure and mechanical properties of the rheo-squeeze casting AZ91−1Ce−2Ca alloy was studied.The results indicate that with the increase of Ca content,the microstructure is refined and the flame resistance of the AZ91−1Ce−xCa alloys increases.But when the Ca content exceeds 1 wt.%,with the Ca content increasing,the mechanical properties of the AZ91−1Ce−xCa alloys reduce rapidly.For rheo-squeeze casting process,the increase of applied pressure and rotation speed can both bring about significant refinement in the microstructure of the AZ91−1Ce−2Ca alloy and reduction of the porosity,so the mechanical properties increase.Compared to conventional casting,the AZ91−1Ce alloy with the addition of 2 wt.%Ca by rheo-squeeze casting not only guarantees the oxidation resistance(801℃),but also improves mechanical properties.展开更多
The structure, Curie temperature and magnetostriction of Pr_ 0.1Ce_ 0.6Tb_ 0.3Fe_ 1.9-xB_x compounds were investigated by means of X-ray diffraction using a Vibrating sample magnetometer and a standard strain techniqu...The structure, Curie temperature and magnetostriction of Pr_ 0.1Ce_ 0.6Tb_ 0.3Fe_ 1.9-xB_x compounds were investigated by means of X-ray diffraction using a Vibrating sample magnetometer and a standard strain technique. All the samples show entire MgCu_2-type laves phase structure. The lattice parameter decreases slightly when x≤0.1, and decreases rapidly when x>0.1 with increasing B content. Curie temperature exhibits a peak at x=0.1. The substitution of B for Fe causes the decrease of magnetostriction at room temperature.展开更多
Rapidly solidified（RS） Mg-6Zn-1Y-1Ce ribbons were prepared by single roller melt-spinning technique.Transmission electron microscopy and energy dispersive X-ray spectroscopy were employed to characterize the microst...Rapidly solidified（RS） Mg-6Zn-1Y-1Ce ribbons were prepared by single roller melt-spinning technique.Transmission electron microscopy and energy dispersive X-ray spectroscopy were employed to characterize the microstructure of RS ribbons.The results show that there is high density of particles distributed within grains and at grain boundaries in the region near wheel side.The particle density is decreased in the middle region and free surface region.The alloy is predominantly composed of supersaturated--Mg solid solution,T phase and W phase;meanwhile,a few icosahedral quasicrystalline and Mg4Zn7 particles are also observed.The T phase is confirmed having a body-centered orthorhombic structure that is transformed from the body-centered tetragonal structure Mg12Ce phase due to the partial substitution of Mg atoms by Zn.展开更多
Sm and Gd co-doped Ceria (SGDC:Sm_(0.1)Gd_(0.1)Ce_(0.8)O_(1.90)) films as the electrolytes were investigated for the IT-SOFCs (intermediate-temperature solid oxide fuel cells).SGDC sensing films were successfully prep...Sm and Gd co-doped Ceria (SGDC:Sm_(0.1)Gd_(0.1)Ce_(0.8)O_(1.90)) films as the electrolytes were investigated for the IT-SOFCs (intermediate-temperature solid oxide fuel cells).SGDC sensing films were successfully prepared on the Al_2O_3 substrates by RF-magnetron sputtering.The relationship between sputtering parameters and film microstructure was discussed, and the optimum parameters were gained.The crystal structure analysis and surface morphologic observation of the SGDC films were carried out through X-ray diffraction (XRD) and scanning electron microscopy (SEM).The oxygen ion conductivity of the SGDC film was evaluated by AC impedance spectroscopy at the different temperatures.The XRD analysis shows that the SGDC films grow preferentially along the (111) compact plane.The crystallinity of the SGDC films is enhanced with the increase of the RF sputtering power from 150 W to 250 W.The oxygen ion conductivity of the SGDC was measured at the temperature from 600℃to 800℃in air by AC impedance spectroscopy.The result shows that a high oxygen ion conductivity of 2.44×10^(-2) S.cm^(-1) was achieved at 800℃.展开更多
基金financial supports from National Natural Science Foundation of China(Nos.51775334,51771115,U2037601)Research Program of Joint Research Center of Advanced Spaceflight Technologies,China(No.USCAST2020-14)。
文摘The microstructure,mechanical properties and flame resistance behavior of the AZ91−1Ce alloys with different Ca additions were firstly investigated.Then,the effect of processing parameters,including applied pressures and rotation speeds,on the microstructure and mechanical properties of the rheo-squeeze casting AZ91−1Ce−2Ca alloy was studied.The results indicate that with the increase of Ca content,the microstructure is refined and the flame resistance of the AZ91−1Ce−xCa alloys increases.But when the Ca content exceeds 1 wt.%,with the Ca content increasing,the mechanical properties of the AZ91−1Ce−xCa alloys reduce rapidly.For rheo-squeeze casting process,the increase of applied pressure and rotation speed can both bring about significant refinement in the microstructure of the AZ91−1Ce−2Ca alloy and reduction of the porosity,so the mechanical properties increase.Compared to conventional casting,the AZ91−1Ce alloy with the addition of 2 wt.%Ca by rheo-squeeze casting not only guarantees the oxidation resistance(801℃),but also improves mechanical properties.
文摘The structure, Curie temperature and magnetostriction of Pr_ 0.1Ce_ 0.6Tb_ 0.3Fe_ 1.9-xB_x compounds were investigated by means of X-ray diffraction using a Vibrating sample magnetometer and a standard strain technique. All the samples show entire MgCu_2-type laves phase structure. The lattice parameter decreases slightly when x≤0.1, and decreases rapidly when x>0.1 with increasing B content. Curie temperature exhibits a peak at x=0.1. The substitution of B for Fe causes the decrease of magnetostriction at room temperature.
基金Project (50271054) supported by the National Natural Science Foundation of ChinaProject (20070700003) supported by the Doctorate Programs Foundation of Ministry of Education of China+1 种基金Project (102102210031) supported by the Science and Technologies Foundation of Henan Province,ChinaProject (2010A430008) supported by the Natural Science Foundation of Henan Educational Committee of China
文摘Rapidly solidified（RS） Mg-6Zn-1Y-1Ce ribbons were prepared by single roller melt-spinning technique.Transmission electron microscopy and energy dispersive X-ray spectroscopy were employed to characterize the microstructure of RS ribbons.The results show that there is high density of particles distributed within grains and at grain boundaries in the region near wheel side.The particle density is decreased in the middle region and free surface region.The alloy is predominantly composed of supersaturated--Mg solid solution,T phase and W phase;meanwhile,a few icosahedral quasicrystalline and Mg4Zn7 particles are also observed.The T phase is confirmed having a body-centered orthorhombic structure that is transformed from the body-centered tetragonal structure Mg12Ce phase due to the partial substitution of Mg atoms by Zn.
文摘Sm and Gd co-doped Ceria (SGDC:Sm_(0.1)Gd_(0.1)Ce_(0.8)O_(1.90)) films as the electrolytes were investigated for the IT-SOFCs (intermediate-temperature solid oxide fuel cells).SGDC sensing films were successfully prepared on the Al_2O_3 substrates by RF-magnetron sputtering.The relationship between sputtering parameters and film microstructure was discussed, and the optimum parameters were gained.The crystal structure analysis and surface morphologic observation of the SGDC films were carried out through X-ray diffraction (XRD) and scanning electron microscopy (SEM).The oxygen ion conductivity of the SGDC film was evaluated by AC impedance spectroscopy at the different temperatures.The XRD analysis shows that the SGDC films grow preferentially along the (111) compact plane.The crystallinity of the SGDC films is enhanced with the increase of the RF sputtering power from 150 W to 250 W.The oxygen ion conductivity of the SGDC was measured at the temperature from 600℃to 800℃in air by AC impedance spectroscopy.The result shows that a high oxygen ion conductivity of 2.44×10^(-2) S.cm^(-1) was achieved at 800℃.
