材料期刊网

INVESTIGATION OF INFLUENCE OF HYDROGEN ATTACK ON FATIGUE PROPERTIES OF PRESSURE VESSEL STEELS

J.L. Li , K.F. Wang , J. Li , Z.M. Yao and W. Ke(Fushun Petroleum Institute , Fushun 113001 , China)(Department of Chemical Engineering , Zhejiang University , Hangzhou 310027 , China)(Institute of Corrosion and Protection of Metals , The Chinese Academy of Sciences , Shengyang 110015 , China)

金属学报(英文版)

Influence of hydrogen attack on mechanical and fatigue properties of 1020, 15CrMo and 2.25Cr-1Mo steels has been studied, which were exposed to gaseous hydrogen at pressure of 18MPa and 300-480℃ for up to 480h. The results of fatigue test showed that hydrogen attack (HA) resulted in an obvious change in fatigue properties of 1020 and 15CrMo steels, however, 2.25Cr-1Mo steel showed a lower susceptibility to hydrogen attack due to the addition of Cr and Mo. Fatigue crack behaviour for 1020 steel is attributed to hydrogen attack damage and the crack closure induced by the rough cracking surface, which lead to a valley on △Kth～HA% plot. The change in the fatigue behaviour of 15CrMo steel is possibly caused by severe surface decarburization.

关键词: hydrogen attack , null , null , null

F、K、Na对烧结固相反应影响的研究

王艺慈 , 罗果萍 , 柏京波 , 郝志忠 , 邬虎林

钢铁

采用差热分析（DTA）与X射线衍射（XRD）相结合的方法，研究了高碱度烧结矿中F、K、Na对烧结固相反应开始温度与最初形成产物的影响规律，研究结果表明：烧结原料中F、K、Na的存在，促进了烧结固相反应过程中低熔点化合物硅酸钠、铁酸钠、枪晶石的形成，固相反应过程中硅酸钠自702 ℃，铁酸钠自780 ℃，枪晶石自900 ℃开始合成，从而探明了F、K、Na在烧结固相反应过程中的行为规律。

关键词: 烧结固相反应;固相反应开始温度;最初形成产物

F、K、Na对烧结固相反应影响的研究

王艺慈 , 罗果萍 , 柏京波 , 郝志忠 , 邬虎林

钢铁

采用差热分析(DTA)与X射线衍射(XRD)相结合的方法,研究了高碱度烧结矿中F、K、Na对烧结同相反应开始温度与最初形成产物的影响规律,研究结果表明:烧结原料中F、K、Na的存在,促进了烧结固相反应过程中低熔点化合物硅酸钠、铁酸钠、枪晶石的形成,固相反应过程中硅酸钠自702℃,钦酸钠自780℃,枪晶石自900℃开始合成,从而探明了F、K、Na在烧结固相反应过程中的行为规律.

关键词: 烧结固相反应 , 固相反应开始温度 , 最初形成产物

Oxidation behavior of sputtered microcrystalline coating of superalloy K17F at high temperature

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

The influence of sputtering on the high temperature oxidation resistance of the cast superalloy M17F has been studied. The as-sputtered microcrystalline layer has a homogeneous gamma phase structure with very fine gl ain size (20-100 nm), while the as-cast alloy is composed of gamma, gamma' and carbides. The oxidation resistance of the microcrystalline coating of K17F alloy is much better than that of the as-cast alloy, and is even superior to that of the pack aluminized alloy. At the initial oxidation stage, the oxide scale which formed on the as-cast alloy is composed of complex oxides of Cr, Ti, Ni and Al. As the: oxidation time is prolonged, the amount of alpha-Al2O3 increases and becomes the main product. However, the scale which formed on the microcrystalline coating consists only of alpha-Al2O3. Cyclic oxidation and acoustic emission examination showed that the oxide scale on the cast M17F alloy easily spalled during cooling, but the alpha-Al2O3 scale on the sputtered layer had excellent adhesion. The beneficial effects of microcrystalline structure on oxidation resistance are discussed briefly.

关键词: K17F;sputtering;oxidation behavior

Li,K|F,Cl互易系熔盐溶液的分子动力学计算机模拟研究

邵俊 , 徐桦 , 陈念贻

金属学报

用分子动力学方法对Li,K?F,Cl系熔盐溶液进行了计算机模拟研究。计算了径向分布函数、偏克分子混合能等热力学性质以及Li~+,K~+,F~-和Cl~-的扩散系数。计算值与实验值大体符合。根据计算结果,讨论了熔盐溶液中离子和空孔分布的规律。

关键词: 碱卤化物熔盐 , molecular dynamics , computerized simulation

水热法生长非线性光学晶体K4Gd2(CO3)3F4

吴振雄 , 何小玲 , 周海涛 , 涂衡 , 岳银超 , 张昌龙 , 胡章贵

人工晶体学报

采用水热法,探索了 K4Gd2(CO3)3F4晶体的析晶条件,诸如生长原料及配比、生长温度、生长周期等,并成功生长了毫米级的透明单晶.对生长的晶体进行了XRD、UV-Vis-NIR、SHG等测试,结果表明,K4Gd2( CO3)3F4晶体在380～2000 nm波段的透过率超过80％,紫外吸收截止边低于200nm；其二阶非线性光学效应约为KDP的3.5倍.

关键词: 非线性光学晶体 , K4Gd2(CO3)3F4晶体 , 水热法

Synthesis and superconductivity of Nd0.7Sr1.3Cu(O,F)(4-delta) with T-c=44 K

Physica C-Superconductivity and Its Applications

Superconducting cuprate fluorides Nd0.7Sr1.3Cu(O,F)(4-delta) with T-c = 44 K were obtained by solid phase fluorination of the T-structure Nd0.7Sr1.3CuO4-gamma at low temperature (200-300 degrees C) using CuF2 as fluorinating reagent. The oxyfluoride has K2NiF4 structure with S.G. I4/mmm as its precursors, but the evident lattice expansions were observed. The a-axis expands from 3.7257(2) Angstrom to 3.9288(5) Angstrom and c-axis from 12.8240(3) Angstrom to 12.9630(2) Angstrom. No trace of SrF2 was detected in these fluorinated products. XRD and magnetic measurement revealed that the superconductivity in the fluorinated products originated from the oxyfluorides with reduced CuO2 plane and in the presence of the apical anion.

关键词: hole concentration;copper;route;a=ca;tc

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

Analysis of exchange interaction for heterodinuclear Cu-F-Mn clusters in K2CuF4 : Mn2+ and KZnF3 : Cu2+-Mn2+ systems

Physica B-Condensed Matter

The antiferromagnetic phenomena of the heterodinuclear Cu-F-Mn clusters in K2CuF4: Mn2+ and KZnF3: Cu2+- Mn2+ systems have been studied by the use of the heterodinuclear magnetic formula and the effective potential method. In our calculations two different models which are associated, respectively, with the elongated and the compressed Jahn-Teller distortion along the Cu-F-Mn direction have been taken for describing the located structures in KZnF3: Cu2+-Mn2+ system. It is demonstrated that the strong antiferromagnetic exchange interaction in KZnF3: Cu2+-Mn2+ which is about two times larger than that in K2CuF4:Mn2+ may be attributed to the Jahn-Teller compressed distortion in KZnF3:Cu2+-Mn2+. The theoretical values 2J = -143.4 and -59.9 cm(-1) are in good agreement with the experimental findings, 2J = 130 +/- 10cm(-1) in KZnF3:Cu2+ -Mn2+ and 2J = -52 +/- 2cm(-1) in K2CuF4:Mn2+ respectively. (C) 2001 Published by Elsevier Science B.V.

关键词: exchange interaction;antiferromagnetism

Investigations of EPR g Factors and Rhombic Distortion for the Rhombic Cu2+ Centers in K2Zn1-x Cu (x) F-4 Crystals at Low Temperature

Applied Magnetic Resonance

The electron paramagnetic resonance g factors g (i) (i = x, y, z) of two rhombic Cu2+ centers, Cu2+(II) and Cu2+(III), in K2Zn1-x Cu (x) F-4 crystals found at low temperature are calculated from the complete diagonalization (of energy matrix) method based on the cluster approach. The calculations show that the ground state wave function of the two rhombically compressed Cu2+ centers is with a small admixture of . The rhombic distortions for both Cu2+ centers are obtained from the calculations. The results are discussed.

关键词: electron-paramagnetic-resonance;atomic screening constants;hyperfine;parameters;gyromagnetic factor;spin resonance;scf functions;field;copper(ii);dependence;spectra