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INTERACTION OF PRECIPITATION AND RECRYSTALLIZATION IN RAPIDLY SOLIDIFIED Cu-Cr-Zr-Mg ALLOY

Liu , B.X. Kang , X.G. Cao , J.L. Huang , B. Yinand H.C. Gu (Institute of Materials Science and Engineering , Xi'an Jiaotong University , Xi'an 710049 , China)(Institute of Materials Science and Engineering , Xi'an Jiaotong University , Xi'an 710049 , China)( Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471049 , China)( Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471049 , China)( Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471049 , China)( Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471049 , China)

金属学报(英文版)

In this paper; the recrystallization process during aging for a rapidly solidified Cu-Cr-Zr-Mg alloy has been investigated. It is found that the discotinuous crystallization process has been partially retarded by the ultra-fine and dispersed precipitation upon aging after deformation. Thus, a phenomenon of combined in situ and discontinuous recrystallization has been observed in the rapidly solidified Cu-Cr-Zr-Mg alloy.On the nucleation and growth of recrystallization, the precipitated phases are coarscned and dissolved in the front of grain boundaries following a re-precipitation in the recrystallization area,which results in the much more dispersed precipitates.

关键词: rapid solidification; Cu-Cr-Zr-Mg alloy; aging precipitation; recrystallization

ATOMIC SCALE MECHANISM OF RESTRAINED EMBRITTLEMENT IN AMORPHOUS Fe_(78)B_(13)Si_9 ALLOY BY ELECTRIC PULSE RAPID ANNEALING

J.L. Huang , X.G. Cao , E. Sukedai , S. Yamasaki , and H.C.Gu(Department of Materials Engineering , Luoyang Institute of Technology , Luoyang 471039 , China)(Department of Mechanical Engineering , Okayama University of Science , 1-1 Ridai-Cho , Okayama City , Okayma 700 , Japan)(Institute of Materials Science and Engineering , Xi'an Jiaotong University , Xi'an 710049 , China)

金属学报(英文版)

The direct observations of the atomic arrangements in both conventional furnace annealed and electric pulse rapid annealed Fe78B13Si9 amorphous alloy have been conducted by the lattice imaging technique in a higt resolution electron microscope. The results showed that the embrittlement of the alloy was related to the extent of atomic rearrangements during the annealing processes. The embrittlement of the alloy after 1hour conventional furnace annealing at about 270℃ is caused by the sufficient atomic rearrangements which are characterized by the growth of some bct Fe3B-like atomic short range ordering regions already existed in the as-quenched structure. Electric pulse rapid annealing can effectively retard the above-mentioned atomic rearrangements and thus restrain the embrittlement. The embrittlement only occurs when certain amount of bcc α-Fe nanocrystals are precipitated in the amorphous matrix during electric pulse rapid annealing.

关键词: Fe_(78)B_(13)Si_9 amorphous alloy , null , null , null

Investigations of the g factors of Fe+ in MgO and CaO

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The g factors of Fe+ in MgO and CaO are theoretically investigated by the perturbation formula of the g factor of a V ion in cubic octahedral symmetry based on the cluster approach. By considering the partial quenching of the spin-orbit coupling interaction and the effective Lande factor due to the dynamic Jahn-Teller effect (DJTE), the experimental g factors of the studied systems are reasonably interpreted. It can be suggested that the small g factors of the Fe+ centers in MgO and CaO can be likely attributed to the DJTE, rather than the covalency effect within the scheme of the static crystal-field model.

关键词: electron paramagnetic resonance;crystal- and ligand-field theory;Fe+;MgO;CaO;atomic screening constants;electron spin resonance;paramagnetic-resonance;orbit interaction;scf functions;crystals;spectra;oxide;co2+

Theoretical studies of the g factors for Co2+ in MgO and CaO crystals

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

This paper presents a cluster approach to the calculation of the g factors for 3d(7) ions in cubic octahedral crystals, in which the parameters related to the configuration interaction and the covalency reduction effects are obtained from optical spectra of the studied crystals, and so no adjustable parameters are applied. From the approach, the g factors for MgO:Co2+ and CaO:Co2+ are calculated. The calculated results show good agreement with the observed values. The experimental values of g < 4.333 (the first order value in absence of configuration and covalency interactions) for MgO:Co2+ and g > 4.333 for CaO:Co2+ are also explained.

关键词: electron paramagnetic resonance (EPR);crystal-field theory;Co2+ ion;MgO;CaO

Complete ligand-field calculations of energy spectrum and g factor of CaO : Ni2+ and their pressure-induced shifts

Communications in Theoretical Physics

The calculations of the whole energy spectrum and the g factor of the ground state for CaO:Ni2+ at normal pressure and their pressure-induced shifts have been carried out on the basis of the theory of pressure-induced shifts and the diagonalization of the complete dg energy matrix in a regular octahedral field. The calculated results are in very good agreement with experimental data. The physical essentials of the pressure-induced shifts of typical levels and g factor for the ground state have been revealed by using the wavefunctions and energy spectra at various pressures.

关键词: high pressure;ligand field;energy spectra;optical properties;electronic spin resonance

X射线荧光光谱法测定转炉渣中CaO,MgO,SiO2

李华斌

冶金分析 doi:10.3969/j.issn.1000-7571.2003.06.021

试样用硼砂镶边衬底压片,以铑靶的康普顿散射线强度为内标,X射线荧光光谱法测定转炉渣中CaO,MgO和SiO2的含量,结果令人满意.

关键词: X射线荧光光谱法 , 转炉渣 , CaO , MgO , SiO2

(MgO)0.1-x(CaO)x(ZrO2)0.9陶瓷的相组成、力学与抗热震性能研究

樊传刚 , 徐兰 , 严解荣 , 朱义文 , 于洋 , 李家茂

耐火材料 doi:10.3969/j.issn.1001-1935.2007.02.007

首先以电熔ZrO2为主原料,以碱式碳酸镁和CaCO3为稳定剂,经混合、成型和预烧(1 550 ℃ 3 h)后,制成(MgO)0.1-x(CaO)x(ZrO2)0.9系列陶瓷粉体(x值分别取0、0.01、0.02、0.03、0.04、0.05、0.1);然后将预烧后试样破碎、筛分成0.1～0.074 mm的粗粒级颗粒和＜0.055 mm的细粒级颗粒,分别按单一细颗粒和粗颗粒与细颗粒混合(粗、细颗粒质量比为1∶1)两种方案进行坯体配料,经1 550 ℃ 5 h 烧成后制成(MgO)0.1-x(CaO)x(ZrO2)0.9系列陶瓷试样,研究了稳定剂组成的相对变化对试样的相组成、体积密度、力学性能与抗热震性能的影响.结果表明:(1)在稳定剂MgO、CaO总量10%(摩尔分数)不变的情况下,试样中立方相含量随着CaO量(即x值)增加而增加;当x=0.01时,陶瓷中单斜相与立方相含量之比为21,此时陶瓷具有较高的常温抗折强度和较为理想的抗热震性(1 100 ℃水急冷5次后未出现裂纹),而且其抗热震性受陶瓷材料致密度的影响程度较小.(2)在陶瓷粉体中增加粗粒级配料,可有效降低ZrO2陶瓷试样的致密度,提高试样的抗热震性能,但其抗折强度也随之下降.

关键词: ZrO2陶瓷 , 部分稳定氧化锆(PSZ) , 复合稳定剂 , 相组成 , 力学性能 , 抗热震性

CaO在CaCl2和等摩尔CaCl2-X(X=NaCl, BaCl2,LiCl)熔盐中的阴极行为

王淑兰 , 王伟 , 王川华 , 张丽君

金属学报

采用循环伏安方法研究了1173 K时CaCl2-0.5%CaO (摩尔分数)和等摩尔CaCl2-X-0.5%CaO(X=NaCl, BaCl2, LiCl) 熔盐中CaO在Mo电极上的阴极行为.研究结果表明,CaCl2与CaO电离的Ca2+具有不同的离子结构和还原电势, 在1173K时其还原峰电势分别为-2.15和-1.51 V.等摩尔混合熔盐CaCl2-x-0.5%CaO (x=NaCl, BaCl2)中,CaO诱发电解质产生低电位沉积, 降低了混合熔盐的电化学稳定性.通过阴极扫描电流峰密度与扫描速率的关系, 计算出1173K时CaO电离的Ca2+在CaCl2-0.5%CaO,等摩尔的CaCl2-NaCl-0.5%CaO,CaCl2-BaCl2-0.5%CaO和CaCl2-LiCl--0.5%CaO熔盐中的扩散系数,分别为6.42×10-5, 1.56×10-5,1.20×10-5和 6.79×10-5cm2/s.

关键词:

CaO在CaCl2和等摩尔CaCl2-X(X=NaCl,BaCl2,LiCl)熔盐中的阴极行为

王淑兰 , 王伟 , 王川华 , 张丽君

金属学报 doi:10.3321/j.issn:0412-1961.2008.06.018

采用循环伏安方法研究了1173 K时CaCl2-0.5%CaO(摩尔分数)和等摩尔CaCl2-X-0.5%CaO(X=NaCl,BaCl2,LiCl)熔盐中CaO在Mo电极上的阴极行为.研究结果表明,CaCl2与CaO电离的Ca计具有不同的离子结构和还原电势,在1173 K时其还原峰电势分别为-2.15和-1.51 V.等摩尔混合熔盐CaCl2-x-0.5%CaO(x=NaCl,BaCl2)中,CaO诱发电解质产生低电位沉积,降低了混合熔盐的电化学稳定性.通过阴极扫描电流峰密度与扫描速率的关系,计算出1173 K时CaO电离的Ca2+在CaCl2-0.5%CaO,等摩尔的CaCl2-NaCl-0.5%CaO,CaCl2-BaCl2-0.5%CaO和CaCl2-LiCl-0.5%CaO熔盐中的扩散系数,分别为6.42×10-5,1.56×10-5,1.20×10-5和6.79×10-5 cm2/s.