To investigate potential strengthening approaches,multi-layered zirconium–titanium(Zr-Ti)composites were fabricated by hot-rolling bonding and annealing.The microstructures of these composites were characterized usin...To investigate potential strengthening approaches,multi-layered zirconium–titanium(Zr-Ti)composites were fabricated by hot-rolling bonding and annealing.The microstructures of these composites were characterized using scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)and electron backscatter diffractometry(EBSD).Their mechanical properties were evaluated by uniaxial tension and compression measurements.It was found that the fabricated Zr–Ti composites are composed of alternating Zr/diffusion/Ti layers,and chemical compositions of Zr and Ti showed a gradient distribution in the diffusion layer.Compared with as-rolled samples,annealing can strengthen the layered gradient Zr–Ti composite,and this is mainly caused by solid-solution strengthening and microstructure refinement-induced strengthening.Compared with the raw materials,a synergistic improvement of strength and ductility is achieved in the Zr–Ti composite as a result of the layered gradient microstructure.Tension–compression asymmetry is observed in the Zr–Ti composites,which may be attributed to twinning and microvoids induced by unbalanced diffusion.展开更多
Amorphous CoxC1-x granular films were prepared on n-Si（100） substrate by dc magnetron sputtering. The effects of Co con- centration, film thickness and annealing temperature on the magnetic properties and magnetores...Amorphous CoxC1-x granular films were prepared on n-Si（100） substrate by dc magnetron sputtering. The effects of Co con- centration, film thickness and annealing temperature on the magnetic properties and magnetoresistance （MR） were investigated After annealing at 500℃ for 0.5 hour, the Co（002） peak of the CoxC1-x（x〉2.5 at.%） films was observed, but cracks appeared in the films. Saturation magnetization Ms increased steadily with the increase of Co concentration from 2.5 at.% to 50 at.% and also increased with annealing temperature from room temperature to 400℃. The coercivity of CoxC1-x films was less than 180 Oe. The as-deposited Co2.5C97.5 granular films with 80 nm thickness showed a highly positive MR, up to 15.5% at a magnetic field of 0.8 T, observed at T=300 K when the external magnetic field was perpendicular to the film surface. With increasing film thickness and annealing temperature, the value of MR was found to decrease gradually and changed from positive to neg- ative. The MR effect of the CoxC1-x granular films can be explained by p-n heterojunction theory and interface scattering ef- fect.展开更多
In this paper, the structure and magnetic properties of FeRh alloy thin films with a small amount of Pt doping fabricated onto a glass substrate by sputtering are investigated systematically. XRD results show that the...In this paper, the structure and magnetic properties of FeRh alloy thin films with a small amount of Pt doping fabricated onto a glass substrate by sputtering are investigated systematically. XRD results show that the diffraction pattern of as-deposited film exhibits only nonmagnetic y phase. After annealing, the disordered γphase transforms to an ordered α＇ phase. The temperature dependence of saturation magnetization of different annealing times and Pt contents are characterized. The phase transition temperature increases as the Pt component is increased, but the saturation magnetization reduces as the Pt component is in- creased. These results may be caused by the growth of the disordered γ phase.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51971041)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-msxm X0234)。
文摘To investigate potential strengthening approaches,multi-layered zirconium–titanium(Zr-Ti)composites were fabricated by hot-rolling bonding and annealing.The microstructures of these composites were characterized using scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)and electron backscatter diffractometry(EBSD).Their mechanical properties were evaluated by uniaxial tension and compression measurements.It was found that the fabricated Zr–Ti composites are composed of alternating Zr/diffusion/Ti layers,and chemical compositions of Zr and Ti showed a gradient distribution in the diffusion layer.Compared with as-rolled samples,annealing can strengthen the layered gradient Zr–Ti composite,and this is mainly caused by solid-solution strengthening and microstructure refinement-induced strengthening.Compared with the raw materials,a synergistic improvement of strength and ductility is achieved in the Zr–Ti composite as a result of the layered gradient microstructure.Tension–compression asymmetry is observed in the Zr–Ti composites,which may be attributed to twinning and microvoids induced by unbalanced diffusion.
基金supported by the National Natural Science Foundation of China (Grant No. U0734001)the Fundamental Research Funds for the Central Universities, South China University Of Technology (Grant No. 2009ZM0247)
文摘Amorphous CoxC1-x granular films were prepared on n-Si（100） substrate by dc magnetron sputtering. The effects of Co con- centration, film thickness and annealing temperature on the magnetic properties and magnetoresistance （MR） were investigated After annealing at 500℃ for 0.5 hour, the Co（002） peak of the CoxC1-x（x〉2.5 at.%） films was observed, but cracks appeared in the films. Saturation magnetization Ms increased steadily with the increase of Co concentration from 2.5 at.% to 50 at.% and also increased with annealing temperature from room temperature to 400℃. The coercivity of CoxC1-x films was less than 180 Oe. The as-deposited Co2.5C97.5 granular films with 80 nm thickness showed a highly positive MR, up to 15.5% at a magnetic field of 0.8 T, observed at T=300 K when the external magnetic field was perpendicular to the film surface. With increasing film thickness and annealing temperature, the value of MR was found to decrease gradually and changed from positive to neg- ative. The MR effect of the CoxC1-x granular films can be explained by p-n heterojunction theory and interface scattering ef- fect.
基金supported by the National Natural Science Foundation of China (Grant No. 50901052)the Program for Young Excellent Talents in Tongji University (Grant No. 2009KJ003)the "Chen Guang" Project(Grant No. 10CG21) of the Shanghai Municipal Education Commission and Shanghai Education Development Foundation
文摘In this paper, the structure and magnetic properties of FeRh alloy thin films with a small amount of Pt doping fabricated onto a glass substrate by sputtering are investigated systematically. XRD results show that the diffraction pattern of as-deposited film exhibits only nonmagnetic y phase. After annealing, the disordered γphase transforms to an ordered α＇ phase. The temperature dependence of saturation magnetization of different annealing times and Pt contents are characterized. The phase transition temperature increases as the Pt component is increased, but the saturation magnetization reduces as the Pt component is in- creased. These results may be caused by the growth of the disordered γ phase.
