The effect of Ce content(0–1.6 wt.%)on the modification of Mg_(2)Si phase in the as-cast Mg-5Al-2Si alloy was investigated.The original Chinese script type Mg_(2)Si phase was refined distinctly and transformed to dis...The effect of Ce content(0–1.6 wt.%)on the modification of Mg_(2)Si phase in the as-cast Mg-5Al-2Si alloy was investigated.The original Chinese script type Mg_(2)Si phase was refined distinctly and transformed to dispersive block shape gradually by adding Ce element.The length of Chinese script type Mg_(2)Si phase was reduced from 110 to 50μm with increasing Ce content to 1.6 wt.%.The results calculated by Pandat software indicated that the added Ce element first combined with Si to form CeSi_(2)phase,which could serve as the heterogeneous nucleation of Mg_(2)Si phase due to the small lattice mismatch of 7.97%.The modification of Mg_(2)Si phase was mainly attributed to the facts that Ce changed the growth steps of Mg_(2)Si phase and CeSi_(2)promoted the nucleation of Mg_(2)Si phase.With increasing Ce content from 0 wt.%to 1.6 wt.%,the YS,UTS and EL at 150℃were improved from 67.7 MPa,91.2 MPa and 1.6%to 84.2 MPa,128 MPa and 7.5%,respectively.展开更多
Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/dec.As device dimensions continue to reduce and the demand for high swi...Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/dec.As device dimensions continue to reduce and the demand for high switching ratios for low power consumption increases,the tunnel field-effect transistor(TFET)appears to be a viable device,displaying promising characteristic as an answer to the shortcomings of the traditional MOSFET.So far,TFET designing has been a task of sacrificing higher ON state current for low subthreshold swing(and vice versa),and a device that displays both while maintaining structural integrity and operational stability lies in the nascent stages of popular research.This work presents a comprehensive analysis of a heterojunction plasma doped gate-all-around TFET(HPD-GAA-TFET)by making a comparison between Mg_(2)Si and Si which serve as source materials.Charge plasma technique is employed to implement doping in an intrinsic silicon wafer with the help of suitable electrodes.A low-energy bandgap material,i.e.magnesium silicide is incorporated as source material to form a heterojunction between source and silicon-based channel.A rigorous comparison of performance between Si-based GAA-TFET and HPD-GAA-TFET is conducted in terms of electrical,radio frequency(RF),linearity,and distortion parameters.It is observable that HPD-GAA-TFET outperforms conventional Si-based GAA-TFET with an ON-state current(I_(ON)),subthreshold swing(SS),threshold voltage(V_(th)),and current switching ratio being 0.377 mA,12.660 mV/dec,0.214 V,and 2.985×10^(12),respectively.Moreover,HPD-GAA-TFET holds faster switching and is more reliable than Si-based device.Therefore,HPD-GAA-TFET is suitable for low-power applications.展开更多
Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study....Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.展开更多
Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techni...Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techniques in this study.The eutectic morphology transformed from lamellae to rods with the increasing of the solidification velocity. Simultaneously, the orientation relationship changed from (100)Mg2Si/(100)Al;[110]Mg2si/[110]al to (011)Mg2si/(121)Al;[111]Mg2Si/[111]Al and (010)Mg2Si/(110)Al; [100]Mg2Si/[111]Al. Transformation of the eutectic morphology was related to the change of the preferred orientation of phase Mg2si.展开更多
基金supported by the Major Science and Technology projects in Qinghai province (2018-GX-A1)Global Frontier Program through the Global Frontier Hybrid Interface Materials (GFHIM) of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant No. 2013M3A6B1078874)+1 种基金funded by Shanghai Science and Technology Committee (Grant No. 18511109302)the National Natural Science Foundation of China (Grant No. 51825101)
文摘The effect of Ce content(0–1.6 wt.%)on the modification of Mg_(2)Si phase in the as-cast Mg-5Al-2Si alloy was investigated.The original Chinese script type Mg_(2)Si phase was refined distinctly and transformed to dispersive block shape gradually by adding Ce element.The length of Chinese script type Mg_(2)Si phase was reduced from 110 to 50μm with increasing Ce content to 1.6 wt.%.The results calculated by Pandat software indicated that the added Ce element first combined with Si to form CeSi_(2)phase,which could serve as the heterogeneous nucleation of Mg_(2)Si phase due to the small lattice mismatch of 7.97%.The modification of Mg_(2)Si phase was mainly attributed to the facts that Ce changed the growth steps of Mg_(2)Si phase and CeSi_(2)promoted the nucleation of Mg_(2)Si phase.With increasing Ce content from 0 wt.%to 1.6 wt.%,the YS,UTS and EL at 150℃were improved from 67.7 MPa,91.2 MPa and 1.6%to 84.2 MPa,128 MPa and 7.5%,respectively.
文摘Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/dec.As device dimensions continue to reduce and the demand for high switching ratios for low power consumption increases,the tunnel field-effect transistor(TFET)appears to be a viable device,displaying promising characteristic as an answer to the shortcomings of the traditional MOSFET.So far,TFET designing has been a task of sacrificing higher ON state current for low subthreshold swing(and vice versa),and a device that displays both while maintaining structural integrity and operational stability lies in the nascent stages of popular research.This work presents a comprehensive analysis of a heterojunction plasma doped gate-all-around TFET(HPD-GAA-TFET)by making a comparison between Mg_(2)Si and Si which serve as source materials.Charge plasma technique is employed to implement doping in an intrinsic silicon wafer with the help of suitable electrodes.A low-energy bandgap material,i.e.magnesium silicide is incorporated as source material to form a heterojunction between source and silicon-based channel.A rigorous comparison of performance between Si-based GAA-TFET and HPD-GAA-TFET is conducted in terms of electrical,radio frequency(RF),linearity,and distortion parameters.It is observable that HPD-GAA-TFET outperforms conventional Si-based GAA-TFET with an ON-state current(I_(ON)),subthreshold swing(SS),threshold voltage(V_(th)),and current switching ratio being 0.377 mA,12.660 mV/dec,0.214 V,and 2.985×10^(12),respectively.Moreover,HPD-GAA-TFET holds faster switching and is more reliable than Si-based device.Therefore,HPD-GAA-TFET is suitable for low-power applications.
文摘Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.
文摘Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techniques in this study.The eutectic morphology transformed from lamellae to rods with the increasing of the solidification velocity. Simultaneously, the orientation relationship changed from (100)Mg2Si/(100)Al;[110]Mg2si/[110]al to (011)Mg2si/(121)Al;[111]Mg2Si/[111]Al and (010)Mg2Si/(110)Al; [100]Mg2Si/[111]Al. Transformation of the eutectic morphology was related to the change of the preferred orientation of phase Mg2si.