Multiconfiguration quantum chemical calculation of geometry and electron properties of Fe2Si18 cluster indicates on the predictable change of spin states as a function of the excitation energy beginning from ground st...Multiconfiguration quantum chemical calculation of geometry and electron properties of Fe2Si18 cluster indicates on the predictable change of spin states as a function of the excitation energy beginning from ground state with the total spin S = 4. The charges on the two Fe atoms are quite different as well as the charge distribution on the surrounding Si atoms. Nevertheless the total dipole moment of the cluster is a monotonically decreasing function of the excitation energy and it reaches practically zero value in the first singlet state in which the cluster represents a new version of a quibit system.展开更多
The optical microscopy, scanning electron microscopy （SEM） and energy-dispersive spectrometry （EDS） were used to as-sess the influence of micro-addition of （La＋Yb） on the microstructure and mechanical performan...The optical microscopy, scanning electron microscopy （SEM） and energy-dispersive spectrometry （EDS） were used to as-sess the influence of micro-addition of （La＋Yb） on the microstructure and mechanical performance of the AlSi10Cu3 alloy in heat treatment conditions. It was shown that the appropriate （La＋Yb）addition （0.3 wt.% or 0.6 wt.%） transformed the needle-likeβ-Al5FeSi phase into Chinese script or sphericalα-Al8Fe2Si phase. Eutectic silicon refined the long needle-like particles into granular or round particles at 0.6 wt.% （La＋Yb） content. Moreover, the La3Al11 and YbAl3 phases acted as strengthening phases during the heat treatment processing in the alloy with the addition of （La＋Yb）. Consequently, the alloy with 0.6 wt.% （La＋Yb） exhibited an en-hanced mechanical properties response with ultimate tensile strength, elongation, and hardness at 69.35%, 113.26% and 23.61% higher than those of the unmodified alloy, respectively. Further addition （0.9 wt.%） of （La＋Yb） resulted in the increasing of the black acicular RE-rich intermetallics during heat treatment, which could aggravate the situation of stress concentration leading to deteriora-tion of the mechanical properties of alloy.展开更多
文摘Multiconfiguration quantum chemical calculation of geometry and electron properties of Fe2Si18 cluster indicates on the predictable change of spin states as a function of the excitation energy beginning from ground state with the total spin S = 4. The charges on the two Fe atoms are quite different as well as the charge distribution on the surrounding Si atoms. Nevertheless the total dipole moment of the cluster is a monotonically decreasing function of the excitation energy and it reaches practically zero value in the first singlet state in which the cluster represents a new version of a quibit system.
基金Project supported by the National Natural Science Foundation of China(51364035)Ministry of Education tied up with the Special Research Fund for the Doctoral Program for Higher School(20133601110001)Loading Program of Science and Technology of College of Jiangxi Province(KJLD14003)
文摘The optical microscopy, scanning electron microscopy （SEM） and energy-dispersive spectrometry （EDS） were used to as-sess the influence of micro-addition of （La＋Yb） on the microstructure and mechanical performance of the AlSi10Cu3 alloy in heat treatment conditions. It was shown that the appropriate （La＋Yb）addition （0.3 wt.% or 0.6 wt.%） transformed the needle-likeβ-Al5FeSi phase into Chinese script or sphericalα-Al8Fe2Si phase. Eutectic silicon refined the long needle-like particles into granular or round particles at 0.6 wt.% （La＋Yb） content. Moreover, the La3Al11 and YbAl3 phases acted as strengthening phases during the heat treatment processing in the alloy with the addition of （La＋Yb）. Consequently, the alloy with 0.6 wt.% （La＋Yb） exhibited an en-hanced mechanical properties response with ultimate tensile strength, elongation, and hardness at 69.35%, 113.26% and 23.61% higher than those of the unmodified alloy, respectively. Further addition （0.9 wt.%） of （La＋Yb） resulted in the increasing of the black acicular RE-rich intermetallics during heat treatment, which could aggravate the situation of stress concentration leading to deteriora-tion of the mechanical properties of alloy.
