材料期刊网

HEALING OF HYDROGEN ATTACK CRACK IN AUSTENITE STAINLESS STEEL UNDER HEAT TREATMENT

X.G. Li

金属学报(英文版)

The specimens of 304 austenite stainless steel with the hydrogen attack bubbles orcracks were heat treated at 600℃ for 6h. The SEM and TEM observations on thespecimens before and after the heat treatment showed that the bubbles or cracks could behealed completely by heat treatment. The healing of hydrogen attack bubbles or cracksis closely related to heat diffusion of Fe and C atoms in austenite. The driving forceof crack healing results fram the plastic deforming energy Es induced by the growthof hydrogen attack bubbles or cracks. The critical condition of healing of bubbles orcracks is Es ≥ 2γ/r (where γγ is the surface tension, r is the radius of bubbles or halflength of crack). During healing of the hydrogen attack bubbles or cracks, the recovery,polygonization and recrystallization of the sub-grain also occured.

关键词: stainless steel , null , null , null

Theoretical studies of g factors and defect structures for cubic, tetragonal, and orthorhombic Fe+ Centers in alkali halides MX (M = Li, Na; X = F, Cl)

Communications in Theoretical Physics

The EPR g factors for cubic, tetragonal and orthorhombic Fe+ centers in alkali halides MX (M = Li, Na; X = F, Cl) are calculated from second-order perturbation formulas of g factors based on cluster approach for 3d(7) ions in three symmetries. From calculations, the g factors of these Fe+ centers in MX crystals are reasonably explained and the defect structural data for the tetragonal and orthorhombic Fe+ centers are estimated. The results are discussed.

关键词: crystal;and ligand-field theory;electron paramagnetic resonance;defect structure;atomic screening constants;spin-orbit interaction;superposition model;resonance-spectra;epr parameters;crystal-field;scf functions;ions;co2+

Mg-x Li-Al 变形镁合金微观组织与拉伸性能

许天才 , 彭晓东 , 张玺 , 陈元芳 , 姜军伟 , 陈洁

功能材料 doi:10.3969/j.issn.1001-9731.2014.07.013

利用光学显微镜(OM)、扫描电子显微镜(SEM)、X 射线衍射仪(XRD)分析了 Li 元素对 Mg-x Li-3Al 合金组织的影响,并用电子万能试验机测试合金的拉伸性能.结果表明,Li 含量的变化可以明显改变合金的相组成.当 m (Li)＜5．7％(质量分数)时合金由单一α-Mg 相组成；Li 含量在5．7％~10．3％(质量分数)之间时,合金为α-Mg＋β-Li 双相；m (Li)＞10．3％(质量分数)时合金为单一β-Li 相.合金的塑性随 Li 含量的升高而增加,铸态 LA113合金的延伸率高达37．36％,但挤压态下合金强度随 Li 含量升高而降低,挤压态 LA53合金具有最佳抗拉强度,达到263．28 MPa.当 Li 含量升高,合金中的第二相粒子会出现 Al12 Mg17转变为 LiMgAl2.

关键词: 镁锂合金 , 铸态 , 挤压态 , 微观组织 , 拉伸性能

Investigations of the zero-field splittings and g factors for the rhombic Cr3+-Li+ and Cr3+-Na+ defect centers in Cs2CdCl4 crystals

Physica B-Condensed Matter

The high-order perturbation formulas for the zero-field splitting parameters D and E, and g factor g(x), g(y), g(z) for 3d(3) ions in rhombic symmetry are derived by using a two spin-orbit coupling parameter model, in which both the contributions from the spin-orbit coupling of central d(3) ion and that of the ligands are considered. From these formulas, spin Hamiltonian parameters for the rhombic defect centers Cr3+-Li+ and Cr3+-Na+ in Cs2CdC4, crystals are calculated by considering the suitable defect-induced lattice distortions. The results agree well with the observed values. The contributions to spin Hamiltonian parameters from the spin-orbit coupling of ligands are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词: crystal- and ligand-field theory;electron paramagnetic resonance;spin-orbit coupling;Cr3+;Cs2CdCl4;superposition model;ions

Explanations of the optical spectra and g factor for V3+ ions in ZnX (X = S, Se, Te) crystals

Physica B-Condensed Matter

This paper presents a cluster approach for the calculations of the absorption band positions and the g factor of d(2) tetrahedral cluster. In the approach, the different modifications of e and t(2) orbitals of d electrons and the contribution from the spin-orbit coupling of ligands to the EPR g factor due to the mixing of d(2) ions with the ligands are considered. The calculated band positions and g factor for ZnX : V3+ (X = S, Se, Te) crystals show good agreement with the observed values by using only two adjustable parameters. The contribution from the spin-orbit coupling of ligands to the g factor is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词: crystal- and ligand-field theory;optical spectra;electron paramagnetic;resonance;spin-orbit coupling;V3+ ZnX (X = S, Se, Te);vanadium centers;znte crystals

新型特效Na离子吸附剂Li1+xAlxTi2-x(PO4)3的制备和性能研究

孙建之 , 邓小川 , 宋士涛 , 李法强 , 马培华

无机材料学报 doi:10.3321/j.issn:1000-324X.2006.01.028

采用高温固相法合成了新型特效Na离子吸附剂Li1+xAlxTi2-x(PO4)3.通过对不同条件下合成的样品XRD、SEM及其吸附性能的研究表明,少量Al的加入未影响到LiTi2(PO4)3的晶体结构,但使Li1+xAlxTi2-x(PO4)3对Na离子产生了特效吸附作用.当x=0.4时,在pH值为10.0～11.0条件下,Li1+xAlxTi2-x(PO4)3的吸附容量达到11.76mg/g.另外,本文对材料的激光拉曼光谱和红外光谱进行了研究和指认.

关键词: 吸附剂 , 含锂磷酸盐 , 制备 , 固相反应

Li_1+2x+yAl_xNd_yTi_2-x-ySi_xP_3-xO₁₂系统的锂快离子导体研究

陈瑞福 , 王文继

无机材料学报

Li_1+2x+yAl_xNd_yTi_2-x-ySi_xP_3-xO₁₂ 锂快离子导体（以下简称Al-Nd-Lisicon）可以用精选的天然高岭石Al₄[Si₄O₁₀]（OH）₈为起始原料，经与Li₂CO₃、TiO₂、NH₄H₂PO₄进行高温（800～1000℃）固相反应约20h而制得.一个空间群属于R3c的固溶体导电相可在y=0．5，x≤0.3和y=1.0，x≤0．4的组成范围内发现.该相具有较好的电导性和较低的活化能．起始组成y=1．0,x=0．3的合成物具有最高的电导率，在400℃时；其电导率达到3．08×10^-2S／cm，离子导电激活能为35．2kJ／mol.

关键词: 矿物快离子导体 , null , null

INVESTIGATIONS ON THE g FACTORS AND THE SUPERHYPERFINE PARAMETERS FOR THE TETRAGONAL Pd(3+) CENTERS IN AgX (X = Cl, Br)

International Journal of Modern Physics B

The g factors and the superhyperfine parameters for the tetragonal Pd(3+) centers in AgX (X = Cl, Br) are theoretically investigated from the perturbation formulas of these parameters for a 4d(7) ion in tetragonally elongated octahedra In the calculations, the related molecular or coefficients and the unpaired spin densities of the ligands are determined quantitatively from the cluster approach in a uniform way. Both centers originate from substitutional Pd(3+) on Ag(+) site in AgX, with no charge compensator (silver vacancy) nearby. The [PdX(6)](3-) clusters suffer a relative elongation of 0.01 angstrom (or 0.06 angstrom) along [1 0 0] (or C(4)) axis for X = Cl (or Br) due to the Jahn-Teller effect The calculated g factors and the superhyperfine parameters based on the above Jahn-Teller elongations show good agreement with the experimental data.

关键词: Electron paramagnetic resonance;crystal and ligand fields;Pd(3+);AgCl;AgBr;transition-metal ions;epr spectroscopic investigations;electron-paramagnetic-resonance;atomic screening constants;laser-light;generation;color image-formation;silver bromide;superposition model;scf functions;agbr

Theoretical investigations of the g factors and the local structure for the trigonal Zr(3+) center in X-ray irradiated YSZ

Journal of Alloys and Compounds

The electron paramagnetic resonance (EPR) g factors g(parallel to) and gperpendicular to and the local structure for the trigonal Zr(3+) center in X-ray irradiated yttria-stabilized zirconia (YSZ) are theoretically investigated from the perturbation formulas of the g factors for a 4d(1) ion in trigonally distorted octahedra. Based on the studies, in this trigonal center (characterized as [ZrO(6)](9-) cluster associated with two oxygen vacancies V(o) along the [ 111] axis), the O(2-) ions in the ligand triangles are found to displace towards the neighbouring Vo by about 0.42 Angstrom due to the electrostatic attraction of the V(o). The above displacement is comparable with that (approximate to 0.36 Angstrom) obtained from neutron diffraction measurements and those (approximate to 0.24-0.37 Angstrom) based on the optical spectral analysis and crystal-field calculations in the previous works. Particularly, partial quenching of the spin-orbit (SO) coupling interaction (i.e., gamma(SO) approximate to 0.44) due to the dynamic Jahn-Teller effect (DJTE) and its influence on the g factors, which were ignored by the previous authors, are taken into account in the present work. The validity of the results is discussed. (C) 2004 Elsevier B.V. All rights reserved.

关键词: electron paramagnetic resonance (EPR);defect structure;crystal-fields;and spin Hamiltonian;Zr(3+);yttria-stabilized zirconia (YSZ);oxide fuel-cells;paramagnetic-resonance spectra;yttria-stabilized;zirconia;spin-orbit interaction;single-crystals;electron traps;ions;epr;fabrication;impurity

AN X RAY DIFFRACTION STUDY OF THE AGING TRANSFORMATION IN Al Li Cu Zr ALLOY

Y.H. Wei , L.Q. Hu , L.S. Jian , L. Lu and B.S. Xu College of Materials Science and Engineering , Taiyuan University of Technology , Taiyuan 030024 , China

金属学报(英文版)

Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenched, and beforetheformationofδ’ phasethereexitscontinuous phasetransformation processes, namely ordering ,spinodal de composition and both coexistence. Gunier Preston zone was not found in the aging process ofthestudied alloy.

关键词: Al Li Cu Zr alloy , null , null , null , null