The slip behavior and mechanism of large-size Mo-3Nb single crystal have been investigated and disclosed comprehensively at room temperature by quasi-static compression with various strains.With the increase of deform...The slip behavior and mechanism of large-size Mo-3Nb single crystal have been investigated and disclosed comprehensively at room temperature by quasi-static compression with various strains.With the increase of deformation,the slip traces change from shallow non-uniform slip lines to dense and uniform slip bands.Different slip traces in the same deformation condition were observed,suggesting that the slip traces in the single crystal are controlled by different types and arrangement mechanisms of mobile dislocation.To clarify the relationship between slip behavior and dislocation arrangement,TEM and AFM analyses were performed.Significant discrepancy between the mobility of screw segments and edge segments caused by double cross-slip multiplication mechanism is the reason why different slip features were witnessed.During the whole slip deformation process,screw dislocations play a dominant role and they are inclined to form wall-substructures by interaction and entanglement.With the development of dislocation accumulation,the entangled dislocation walls evolve into dislocation cells with higher stability.展开更多
This work is a study of the effect of co-doping(ZrO_(2))_(0.9)(Sc_(2)O_(3))_(0.1)solid solution with yttria and/or ceria on the phase composition,local structure and transport properties of the crystals.The solid solu...This work is a study of the effect of co-doping(ZrO_(2))_(0.9)(Sc_(2)O_(3))_(0.1)solid solution with yttria and/or ceria on the phase composition,local structure and transport properties of the crystals.The solid solution crystals were grown using directional melt crystallization in cold crucible.We show that ceria co-doping of the crystals does not stabilize the high-temperature cubic phase in the entire crystal bulk,unlike yttria codoping.Ceria co-doping of the(ZrO_(2))_(0.9)(Sc_(2)O_(3))_(0.1)crystals increases their conductivity,whereas the addition of 1 mol.%yttria tangibly reduces the conductivity.Equimolar co-doping of the(ZrO_(2))0.9(-Sc_(2_O_(3))0.1 crystals with ceria and yttria changes the conductivity but slightly.Optical spectroscopy of the local structure of the crystals identified different types of optical centers.We found that the fraction of the trivalent cations having a vacancy in the first coordination sphere in the ceria co-doped crystals is smaller compared with that in the yttria co-doped crystals.展开更多
基金financially supported by the Major Science and Technology Project of Shaanxi Province,China(No.2020zdzx04-02-02)the Key Research and Development Program of Shaanxi,China(Nos.2019ZDLGY05-04 and 2019ZDLGY05-06)the National key Research and Development Program(No.2017YFB0306003)。
文摘The slip behavior and mechanism of large-size Mo-3Nb single crystal have been investigated and disclosed comprehensively at room temperature by quasi-static compression with various strains.With the increase of deformation,the slip traces change from shallow non-uniform slip lines to dense and uniform slip bands.Different slip traces in the same deformation condition were observed,suggesting that the slip traces in the single crystal are controlled by different types and arrangement mechanisms of mobile dislocation.To clarify the relationship between slip behavior and dislocation arrangement,TEM and AFM analyses were performed.Significant discrepancy between the mobility of screw segments and edge segments caused by double cross-slip multiplication mechanism is the reason why different slip features were witnessed.During the whole slip deformation process,screw dislocations play a dominant role and they are inclined to form wall-substructures by interaction and entanglement.With the development of dislocation accumulation,the entangled dislocation walls evolve into dislocation cells with higher stability.
基金Financial support from the Russian Science Foundation(Project 17-79-30071“Scientifically grounded optimization of power and mass-dimensional characteristics of planar SOFC stacksdevelopment of fuel processor for highly-efficient transport and stationary power plants”)is gratefully acknowledged.A part of experimental facilities used for this research were developed in framework of Project 14.B25.31.0018 funded by the Russian Ministry of Education and Science。
文摘This work is a study of the effect of co-doping(ZrO_(2))_(0.9)(Sc_(2)O_(3))_(0.1)solid solution with yttria and/or ceria on the phase composition,local structure and transport properties of the crystals.The solid solution crystals were grown using directional melt crystallization in cold crucible.We show that ceria co-doping of the crystals does not stabilize the high-temperature cubic phase in the entire crystal bulk,unlike yttria codoping.Ceria co-doping of the(ZrO_(2))_(0.9)(Sc_(2)O_(3))_(0.1)crystals increases their conductivity,whereas the addition of 1 mol.%yttria tangibly reduces the conductivity.Equimolar co-doping of the(ZrO_(2))0.9(-Sc_(2_O_(3))0.1 crystals with ceria and yttria changes the conductivity but slightly.Optical spectroscopy of the local structure of the crystals identified different types of optical centers.We found that the fraction of the trivalent cations having a vacancy in the first coordination sphere in the ceria co-doped crystals is smaller compared with that in the yttria co-doped crystals.
