采用光学浮区法生长了层状过渡金属氧化物Bi2Sr2-x Ca x Co2O y(x=0,2)晶体。通过XRD,SEM和TEM结构表征,表明了生长的晶体为层状晶体,并确定了晶体生长的方向垂直与c轴。研究了晶体的热电性能,包括Bi2Ca2Co2O y和Bi2Sr2Co2O y晶体ab面的...采用光学浮区法生长了层状过渡金属氧化物Bi2Sr2-x Ca x Co2O y(x=0,2)晶体。通过XRD,SEM和TEM结构表征,表明了生长的晶体为层状晶体,并确定了晶体生长的方向垂直与c轴。研究了晶体的热电性能,包括Bi2Ca2Co2O y和Bi2Sr2Co2O y晶体ab面的Seeback系数和电阻率,表明了Bi2Ca2Co2O y具有较好的热电势和电导,并分析了电输运性能与晶体失配结构的关系。展开更多
Mg-6Al-2Sr alloys with different Sm contents(0%, 0.5%, 1%, 1.5%, 2%, mass fraction) were prepared by melting and casting method. The effects of Sm on the microstructure and mechanical properties of as-cast Mg-6Al-2Sr ...Mg-6Al-2Sr alloys with different Sm contents(0%, 0.5%, 1%, 1.5%, 2%, mass fraction) were prepared by melting and casting method. The effects of Sm on the microstructure and mechanical properties of as-cast Mg-6Al-2Sr alloys were studied by optical microscope, scanning electron microscope, energy dispersive spectrometer, transmission electron microscope, X-ray diffraction and tensile test. The results show that the microstructure of as-cast Mg-6Al-2Sr alloy is composed of α-Mg, Mg_(17)Al_(12), Mg_(13)Al_(3)Sr and lamellar acicular Al_(4)Sr phase. After adding Sm element, granular block Al2Sm phase appears in the grain. With the increase of Sm content, the discontinuous long strip reticular Mg_(17)Al_(12)phase and the lamellar acicular Al4Sr phase gradually decrease, and the Al_(2)Sm phase increases and distributes more dispersedly, so the alloy microstructure is continuously refined. The average grain size of the alloys decreases at first and then increases with the increase of Sm content. When the Sm content is 1.5 wt%, the average grain size reaches the minimum value of 94.6 μm. With the increase of Sm content, the mechanical properties of the alloy at room temperature first increase and then decrease. When the Sm content is 1.5 wt%, the alloy has the best comprehensive mechanical properties at room temperature.展开更多
基金Project(51975167) supported by the National Natural Science Foundation,ChinaProject(2022ZX01A01) supported by the Key R&D Program in Heilongjiang Province,China。
文摘采用光学浮区法生长了层状过渡金属氧化物Bi2Sr2-x Ca x Co2O y(x=0,2)晶体。通过XRD,SEM和TEM结构表征,表明了生长的晶体为层状晶体,并确定了晶体生长的方向垂直与c轴。研究了晶体的热电性能,包括Bi2Ca2Co2O y和Bi2Sr2Co2O y晶体ab面的Seeback系数和电阻率,表明了Bi2Ca2Co2O y具有较好的热电势和电导,并分析了电输运性能与晶体失配结构的关系。
基金Project(51975167) supported by the National Natural Science Foundation,China。
文摘Mg-6Al-2Sr alloys with different Sm contents(0%, 0.5%, 1%, 1.5%, 2%, mass fraction) were prepared by melting and casting method. The effects of Sm on the microstructure and mechanical properties of as-cast Mg-6Al-2Sr alloys were studied by optical microscope, scanning electron microscope, energy dispersive spectrometer, transmission electron microscope, X-ray diffraction and tensile test. The results show that the microstructure of as-cast Mg-6Al-2Sr alloy is composed of α-Mg, Mg_(17)Al_(12), Mg_(13)Al_(3)Sr and lamellar acicular Al_(4)Sr phase. After adding Sm element, granular block Al2Sm phase appears in the grain. With the increase of Sm content, the discontinuous long strip reticular Mg_(17)Al_(12)phase and the lamellar acicular Al4Sr phase gradually decrease, and the Al_(2)Sm phase increases and distributes more dispersedly, so the alloy microstructure is continuously refined. The average grain size of the alloys decreases at first and then increases with the increase of Sm content. When the Sm content is 1.5 wt%, the average grain size reaches the minimum value of 94.6 μm. With the increase of Sm content, the mechanical properties of the alloy at room temperature first increase and then decrease. When the Sm content is 1.5 wt%, the alloy has the best comprehensive mechanical properties at room temperature.
