oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 78 )

2018 ( 833 )

2017 ( 919 )

2016 ( 1067 )

Custom range...

Search Results: 1 - 10 of 52291 matches for " Mg2Si "
All listed articles are free for downloading (OA Articles)
Page 1 /52291
Display every page Item
Thermal stability of Mg2Si epitaxial film formed on Si(111) substrate by solid phase reaction

Wang Xi-N,Wang Yong,Zou Jin,Zhang Tian-Chong,Mei Zeng-Xi,Guo Yang,Xue Qi-Kun,Du Xiao-Long,Zhang Xiao-N,Han Xiao-Dong,Zhang Ze,

中国物理 B , 2009,
Abstract: A single crystalline Mg$_{2}$Si film was formed by solid phase reaction (SPR) of a Si(111) substrate with an Mg overlayer capped with an oxide layer(s), which was enhanced by post annealing from room temperature to 100~$^\circ$C in a molecular beam epitaxy (MBE) system. The thermal stability of the Mg$_{2}$Si film was then systematically investigated by post annealing in an oxygen-radical ambient at 300~$^\circ$C, 450~$^\circ$C and 650~$^\circ$C, respectively. The Mg$_{2}$Si film stayed stable until the annealing temperature reached 450~$^{\circ}$C then it transformed into amorphous MgO$_{x}$ attributed to the decomposition of Mg$_{2}$Si and the oxidization of dissociated Mg.
Microstructural Characterization of Cast Magnesium Matrix Composites by Raman Microscopy
M.A. Malik,K.N. Braszczyńska-Malik,K. Majchrzak
Archives of Foundry Engineering , 2013,
Abstract: Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Ramanmicroscopy in the composites microstructure.
Ba对原位自生Mg2Si/Mg-Zn-Si复合材料组织与力学性能的影响
陈可,李子全,刘劲松,杨继年,孙颖迪,卞松刚
材料工程 , 2010,
Abstract: 研究添加0.1%~2.0%Ba(质量分数,下同)对高Si原位自生Mg2Si/Mg-Zn-Si复合材料组织和力学性能的影响.结果表明随着Ba含量的增加,初生Mg2Si由树枝晶转变为多面体颗粒,其尺寸先减小后增大;汉字状共晶Mg2Si也先减少后增加;复合材料的力学性能显著改善.当Ba含量为1.0%时,其细化变质效果最好,合金的综合力学性能最佳,这是由于Ba的加入形成了大量细微的BaMg2Si2粒子可作为初生Mg2Si的异质形核核心,从而细化变质了Mg2Si;当Ba含量过高(>1.0%),BaMg2Si2相聚集长大导致了过变质现象,力学性能下降.变质为细小多边形的Mg2Si颗粒减少了加载时应力集中与裂纹产生、扩展;其弥散分布阻碍了变形时位错运动,因此强化了复合材料.
往复挤压Mg-4Al-2Si合金中Mg2Si颗粒形貌与分布
郭学锋,杨文朋,宋佩维
材料工程 , 2011,
Abstract: 使用往复挤压细化Mg-4Al-2Si(AS42)合金组织,利用OM,SEM和TEM研究Mg2Si颗粒形貌和分布特征。结果表明,铸态AS42合金中Mg2Si颗粒呈共晶汉字状和初生块状。共晶Mg2Si经2道次往复挤压后全部破碎,且分布均匀。经6道次挤压后初生Mg2Si颗粒全部破碎,细小的Mg2Si颗粒已基本球化。往复挤压合金中Mg2Si颗粒尺寸遵循Weibull分布,颗粒平均尺寸、标准差和相对密度随挤压道次增加而提高,经过8道次挤压后分别为1.3μm、0.7μm和540%。
mg含量对过共晶铝硅合金组织和性能的影响
金云学,付学慧,郭宇航,张艳
江苏科技大学学报(自然科学版) , 2009,
Abstract: ?研究了不同的mg含量对过共晶铝硅合金组织和性能的影响.利用扫描电镜和金相显微镜观察了过共晶铝硅合金在mg含量不同时和热处理前后的金相组织变化,利用xrd和eds分析了合金中不同金相组织的相,利用硬度计测试了合金的布氏硬度和不同相的维度硬度.实验结果表明:在过共晶铝硅合金中,不同的mg含量在过共晶铝硅合金中生成不同形态的mg2si;热处理使板条状的共晶硅细化成点状,汉字状的mg2si细化变为球状;mg含量在1%~5%的范围内,过共晶铝硅合金的硬度随mg的含量增加而增加,热处理可以显著提高合金的布氏硬度.
Mg2Si基热电材料的性能优化研究及其进展
Research Progress on the Improvement of Thermoelectric Properties of Mg2Si-based Materials

陈君,严磊,王超,赵新为,闵忠华
- , 2018, DOI: 10.3969/j.issn.1001-0548.2018.05.018
Abstract: Mg2Si基半导体是重要的中温热电材料,具有原料丰富、价格低、无毒等优点;其载流子有效质量和迁移率均较高,有望获得优异的电性能,近年来倍受关注。该文综述了Mg2Si基材料的研究进展,重点探讨了提高其热电性能的措施,对比了不同制备方法的优缺点,最后指出了今后的研究方向。分析表明,目前研究主要集中在n型体系,应加强对p型材料的性能优化探索。掺杂对提高热电性能的效果更显著,通过制备工艺的优化,将掺杂和纳米化两种措施结合,可进一步有效优化。
As--Cast Microstructure and its Formation Mechanism in Mg-Based Alloys Containing Ca And Si
含Ca,Si镁合金的铸态组织及其形成机制

AI Yanling,LUO Chengping,LIU Jiangwen,HUANG Yanfei,
艾延龄
,罗承萍,刘江文,黄雁飞

金属学报 , 2005,
Abstract: 利用金相,电子显微镜,X射线衍射仪和X射线能谱仪研究了含Ca,Si镁合金的铸态组织特征.结果表明:含Si较低的合金由镁基体及CaMgSi相组成,而含Si较高的合金由镁基体及CaMgSi和Mg2Si两种相组成.CaMgSi相呈三种不同的形态:离散块状、微细点状和针状,而本身是针状的Mg2Si则以“汉字形”团块的形态存在.根据Mg—Mg2Si—CaMgSi赝三元相图,详细讨论了铸态组织的形成机制.
Preparation of rare-earth element doped Mg2Si by FAPAS
FAPAS法制备稀土掺杂的Mg2Si

Wang Liqi,Meng Qingsen,Fan Wenhao,
王丽七
,孟庆森,樊文浩

半导体学报 , 2012,
Abstract: 采用电场激活压力辅助合成(FAPAS)的方法,制备了稀土Sc、Y掺杂的Mg2Si热电材料,合成温度为1023-1073K,压力为50Mpa,所用时间约15min。所得试样结构均匀致密,平均晶粒尺寸约为1.5~2μm,微量的稀土元素不改变基体的组织形貌。掺杂2500ppmSc的式样有最大的绝对Seebeck系数,在408K达未掺杂式样的1.93倍,掺杂200ppmY的式样具有更好的电导率,在468K为未掺杂式样的1.69倍,而Sc掺杂式样具有更好的综合电性能。这两种掺杂试样的热导率分别为未掺杂试样的70%和84%。因此,这两个试样的热电优值-ZT得到了明显提高,分别在408K和468K时达到未掺杂试样的3.3倍和2.4倍。掺杂2500ppmSc的试样具有最大的ZT值为0.42,大于Y掺杂式样的0.4及未掺杂式样的0.25。Sc掺杂的式样在更低的温度区间有最佳的热电性能。
Densification Behavior of Nanocrystalline Mg2Si Compact in Hot-pressing
Wei XIONG,Xiaoying QIN,Li WANG,
Wei
,XIONG,Xiaoying,QINt,Li,WANG

材料科学技术学报 , 2007,
Abstract: Densification behavior of nanocrystalline Mg2Si (n-Mg2Si) with grain size about 30-50 nm was investigated by hot-pressing at 400℃. The results indicated that the densification process of n-Mg2Si exhibited three linear segments: p<0.3 GPa, 0.3 GPa<p<1.2 GPa, and p>l.2 GPa determined by Heckel formula, among which the third fast increasing segment in high pressure range p>1.2 GPa has seldom been reported in conventional coarse-grained polycrystalline materials. Nevertheless, in the whole pressure range (0.125-1.500 GPa) investigated the densification behavior of n-Mg2Si can be well described by a Kawakita formula p/C=(1/a)p 1/(ab) with constant a=0.452 being in good agreement with the initial porosity of the compact.
稀土Ce对过共晶Mg-Si合金中初生Mg2Si相变质的影响
杜军,吕信裕,李文芳
材料工程 , 2011,
Abstract: 利用Mg-20%(质量分数,下同)Ce中间合金对过共晶Mg-Si合金进行变质处理,研究了Ce加入量对该合金中初生Mg2Si相变质效果(主要是形态)的影响规律,并讨论其变质机制。研究结果表明当加入量达到并超过0.4%以后,稀土Ce可有效变质过共晶Mg-Si合金中的初生Mg2Si相,其形态由粗大树枝晶转变为具有非规则外形的颗粒,且随Ce加入量增加到2.0%,Ce对初生Mg2Si相的变质均未产生明显的过变质现象。变质机理应主要与稀土元素富集于Mg2Si相生长表面并抑制优先生长晶向的生长有关。
Page 1 /52291
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.