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MICROSCOPIC KINETICS OF NON-EQUILIBRIUM SOLIDIFICATION

CAl Yingwen , MAO Xiemin , LI Jianguo , FU HengzhiNorthwestern Polytechnieal University , Xi'an , China Manuscript received 14 March , 1994

金属学报(英文版)

Theoretical model for non -equilibrium solidification is constructed with consideration of diffuse interface and multiphase fluctuation. It can he degenerated to Aziz continuous growth model in the case of mono-atomic approximation. for large undercooling, the change of heat capacity should not he neglected and it usually gives an increase in the interface partition coefficient. Solute trapping may happen at a rather slow growth rate compared with that predicted by other models, because the undercooling and structural relaxation ahead of the S/ L interface lowers the interfacial diffusivity to a great extent. Plase fluctuation has two contending effects, decrease in energy barrier and increase in atomic dragging, therefore exerts dual influences on the partition coefficient.

关键词: diffuse interface , null , null

Sr/Ca比变化对红色荧光粉Cal-xSrxS:Eu2+的影响

胡运生 , 叶红齐 , 庄卫东 , 张书生 , 何华强 , 黄小卫

中国稀土学报

在CO气氛下采用固相反应法合成了发红光的Ca1-xSrxS:Eu2+荧光粉,研究了基质阳离子Sr/Ca比变化对其晶体性质及发光性能的影响.结果表明,随着Sr/Ca比的减少,荧光粉的晶胞参数逐渐降低;同时,由于受电子云膨胀效应和晶体场影响,发射主峰向长波方向移动,红色比逐渐增大,色纯度提高.

关键词: Sr/Ca比 , 晶胞参数 , 发射光谱 , 荧光粉 , 稀土

MECHANICAL REDUCTION OF CuO BY Mg AT ROOM TEMPERATURE

MA Xueming YUE Lanping DONG Yuanda Institute of Solid State Physics , Academia Sinica , Hefei , China

金属学报(英文版)

The mechanical reduction of CuO by pure metallic Mg has been investigated during pulver- izing in ball mill at room temperature.The reduction was towards its completion of an average particle size down to 20 nm after milling for 32 h.The mechanism of the mechanical reduction of oxides seems to be the surface activation of nano-metre sized particles driven by mechani- cal force.

关键词: CuO , null , null , null

VC轧辊凸度的形成及其板形控制能力的研究

白振华 , 李兴东 , 杨杰

上海金属 doi:10.3969/j.issn.1001-7208.2002.05.007

以新型轧机-VC轧机为研究对象,首次给出了VC轧辊在不同油压下的凸度分布计算公式,并分析出VC轧辊各结构参数对其凸度生成的影响规律,同时还以宝钢1550CAL平整机为例,研究了带材的平直度与VC辊内部油压之间的关系.

关键词: VC轧辊 , 凸度分析 , 结构参数 , 平直度

GRAIN BOUNDARY SEGREGATION OF TRACE Sn IN A HIGH INDUCTION ORIENTED SILICON STEEL

ZHAO Yu HE Zhongzhi WENG Yuqing WU Baorong Central Iron and Steel Research Institute , Ministry of Metallurgical Industry , Beijing , China Doctorate Student , Department No.2 , Central Iron and Steel Research Institute , Ministry of Metallurgical Industry , Beijing 100081 , China

金属学报(英文版)

When Sn segregated at grain boundaries of high induction oriented silicon steel,no remarka- ble interaction between Sn and other elements was observed.At the starting temperature of secondary recrystallization,950℃,a certain Sn still segregates at grain boundaries.Sn seems to act as a supplemental inhibitor through grain boundary segregation.According to theoreti- cal analysis,an addition of Sn may decrease the secondary recrystallization temperature of high induction oriented silicon steel,and it is in agreement with the experimental result.

关键词: silicon steel , null , null , null , null

On the Formability of Some Metastable Alloy Phases

Bo TANG , Deshan KANG , Pei QING , Weiming ZHANG and Nianyi CHEN(Shanghai Institute of Metallurgy , Chinese Academy of Sciences , Shanghai , 200050 , China)

材料科学技术(英文)

Pattern recognition and neural network methods have been used to investigate the formability of metastable alloy phases, It has been found that some chemi cal bond parameters Such as valence electron number, electronegativity and metallic radii of cor-nponent elements are the dominating fac tors affecting metastable alloy phase formation. Some semi-empirical rules found in this way may be useful for the construction of expert system for materials design.

关键词:

非晶态形成的临界条件

郑兆勃

金属学报

<正> 根据成核理论,当仅考虑均匀核化时,在过冷熔体中结晶成核率可用下式表示: I=N_v~°kT/(3πα_°~3η)exp(-16πα~3β/3T_rΔT_r~2) (1)其中α=(N_v~°)~(1/3)σ/ΔH_m,β=1ΔH_m/RT_m=T/T_m, ΔT_r=T_m-T/T_m.各参量分别表示:I,成核率(cm~(-3)·s~(-1);N_v~°单位体积中的分子数(cm~(-3);η,粘滞系数(P);σ,比表面能(cal·cm~(-2));ΔH_m,熔化时的焓变(cal·mol~(-1));N,阿佛加德罗常数;v,克分子体积;T,熔体温度(K);T_m,熔点(K);k,玻尔兹曼常数;R,气体常数;α_0,分子直径。

关键词:

Ga掺杂ZnO氧化物的热学性能的研究

马硕章 , 张飞鹏 , 房慧 , 张忻 , 路清梅 , 张久兴

连铸 doi:10.3969/j.issn.1007-5461.2015.01.016

在密度泛函理论和线性响应的密度泛函微扰理论基础上通过第一性原理计算的方法研究了Ga掺杂ZnO氧化物的热学参数和热学性能.计算结果表明, Ga掺杂使ZnO氧化物晶胞增大;在所研究温度范围内,纯的ZnO和Ga掺杂的ZnO的晶格热容均随温度升高不断增大,其晶格热容在最高温度900 K分别达到16.5 Cal.mol-1K-1和31.3 Cal.mol-1K-1.纯的ZnO和Ga掺杂的ZnO的德拜温度θD均随温度升高不断增大.Ga掺杂在ZnO中引入了新的振动模式.

关键词: 材料 , ZnO , Ga掺杂 , 热学性能

EFFECTS OF SLIP MODE ON CYCLIC BEHAVIOR OF PRESTRAINED MATERIALS

CHAI Huifen RUAN Zheng FAN Quncheng (Xi'an Jiaotong University , Xi'an , China CHAI Huifen , associate professor , Department of Materials , Xi'an Jiaotong University , Xi'an 710049 , China

金属学报(英文版)

The cyclic behaviours of two prestrained materials with different slip modes have been com- pared.From the analysis of hysterisis loops,it is suggested that the decrease in back stress dominates the cyclic process of Cu-Zn alloy with planar slip mode,while the decrease in frictional stress is the main factor affecting the behaviour of Cu with wavy slip mode.The re- lation between the dislocation configuration and internal stress has been also discussed.By means of the relation just mentioned,the variations of dislocation configuration before and after fatigue of the two materials,the differences in their softening mechanism and mechani- cal behaviour could be interpreted.

关键词: slip mode , null , null , null

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