材料期刊网

Numerical Simulation and Experiments of Hydroforming of Rectangular-section Tubular Component

Shijian YUAN , Gang LIU , Xianwei TIAN , Z.R.WANG

材料科学技术（英文）

In order to reduce high calibration pressure in hydroforming of components with too small radii, a method was proposed to manufacture automotive hollow components with rectangular shape by relatively lower pressure. The process is simulated and analyzed. It is thought that the friction force between the die surface and tube is a main reason that high pressure is needed to form small radii. Using the method proposed in this paper, a petal-like section shape is first preformed so that the central zones of the four sides of the preform section do not contact with the die sides, thus the tube metal is easy to flow into the transition radii area in calibration stage. Moreover, a positive force along the sides is produced by the internal pressure, which is beneficial to overcome the friction force and push the material into the radii. Therefore, the pressure for forming the transition radii is greatly reduced and the components with small radii can be formed with relatively lower pressure. For the experimental case conducted in this paper, the forming pressure is reduced by about 28.6% than the estimated forming pressure.

关键词: Hydroforming , null , null , null

抗HIC压力容器用钢Q345R-Z35特厚板的开发

许少普 , 崔冠军 , 李治强 , 杨东 , 庞百鸣 , 张智慧

钢铁研究

采用模铸浇注、3 800 mm轧机轧制、正火热处理工艺成功地开发并批量生产了82 mm厚Q345R-Z35锅炉压力容器用钢板,钢板超声波探伤全部符合JB/T 4730--2008一级标准,钢板屈服强度平均为350 MPa,抗拉强度平均为520 MPa,伸长率平均值为28%,平均冲击功为144 J,抗层状撕裂厚度拉伸性能全部合格,抗氢致开裂性(HIC)试验检测结果表明:裂纹敏感率、裂纹长度率、裂纹宽度率均为0.

关键词: 抗氢致裂纹 , 抗层状撕裂 , 特厚压力容器板

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

钛等金属的SUN-Z-R复合技术

吴全兴

钛工业进展 doi:10.3969/j.issn.1009-9964.2001.02.008

关键词:

复合材料z-pinning技术的应用与发展

王晓旭 , 陈利

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2009.06.003

简单介绍了z-pin的种类和复合材料z-pin的拉挤工艺.重点综述了利用热压罐和UAZ~R 两种z-pinning技术及z-pinning在复合材料层板、结构件连接及泡沫夹层复合材料中的应用,同时,提出了当前发展z-pinning技术的对策和建议.

关键词: 层合复合材料 , z-pinning , UAZ~(R) , 复合材料连接 , 泡沫夹层

BST掺杂对Co2Z六角铁氧体相结构及动态电磁参数的影响

黄鹏 , 邓龙江 , 谢建良 , 梁迪飞 , 陈良

功能材料

采用陶瓷工艺制备Co2Z(Ba3(Co0.4Zn0.6)2Fe23.4O41)六角铁氧体,通过二次球磨掺杂少量BST(BaSrTiO3)铁电材料.研究BST掺杂对Z型铁氧体的烧结温度、相结构、晶粒生长及其在频率1MHz～1GHz的动态相对复介电常数(εr=ε′r-iε″r)和相对复磁导率(μr=μ′r-iμ″r)的影响.结果表明:在BST掺杂量为Co2Z一次预烧料重量比的0～1.5%内,随BST含量增加,形成在Z型六角结构相生长同时,伴生M相六角结构和钙钛矿结构的多相结构;六角结构晶粒明显长大,材料密度增加;μr和εr增大;铁磁共振和铁电共振频率点移向低频.当BST掺杂量为1.5%、频率1MHz时,μ′r=28,ε′r=100,相对于纯相Co2Z材料μ′r和ε′r明显提高.

关键词: Z型六角铁氧体 , 烧结温度 , 多相结构 , 复磁导率 , 复介电常数

不同Z值β-Sialon材料的氧化动力学研究

黄朝晖 , 潘伟 , 薛文东 , 孙荣国 , 洪彦若

稀有金属材料与工程

采用非等温动力学方法对反应烧结制得的不同配方Z值β-Sialon材料的氧化行为进行了研究.并得到:各配方Z值β-Sialon,在800℃～900℃开始氧化,1000℃～1360℃为快速温度段,1400℃～1480℃为慢速氧化温度段.表面的氧化膜对材料的氧化有保护作用.不同配方Z值β-Sialon氧化初期为化学控速阶段,方程为lnTdW/dT=ln(A0Po 2ZC/Rα)-Ec/RT,试样氧化反应的表观活化能在238 kJ～285kJ之间;试样的氧化后期为扩散控速阶段,其方程为lnT(W-W0)dW/dT=lnZdA02pPo 2/Rα-ED/RT.试样的氧化反应的表观活化能在286 kJ～390 kJ之间.各配方Z值β-Sialon的抗氧化能力随着Z值增大而呈增强的趋势.

关键词: β-Sialon , 非等温动力学方法 , 氧化动力学方程 , 表观活化能

不同Z值β-SiAlON的显微结构与力学性能

董鹏莉 , 张梅 , 郭敏 , 王习东

耐火材料 doi:10.3969/j.issn.1001-1935.2009.01.006

在1773 K、埋Si3N4粉气氛下,以Si、Al和Al2O3(均为分析纯)为原料合成了Z值分别为0.6、1.3、3.0和4.0的β-SiAlON.试验发现:随着所合成β-SiAlON的Z值从0.6增加至4.0,反应产物中逐渐有Al2O3剩余并生成15R(SiAl4O2N4),而且β-SiAlON的晶体形貌也有较大变化:Z=0.6～3.0时,β-SiAlON由细小晶须伴生转变为具有较大直径和长径比的六方柱状晶交织,且具有较完整的晶体结构,随着Z值的增加,材料的耐压强度和抗折强度同时提高;Z=4.0时,晶体形貌则是片状和具有较大长径比的长片状晶相互交错,和Z=3.0相比,材料的耐压和抗折强度有所下降,这主要取决于不同Z值β-SiAlON的不同晶体形貌及断裂方式.

关键词: β-SiAlON , 显微结构 , 晶须 , 耐压强度 , 抗折强度

奇Z超重核的禁戒α衰变

许昌 , 任中洲

原子核物理评论 doi:10.11804/NuclPhysRev.30.03.308

采用密度依赖的结团模型研究了奇Z超重核的禁戒α衰变,α粒子与子核之间的微观核势通过双折叠模型对M3Y核子-核子相互作用势以及α粒子与子核的密度积分给出.α粒子与子核之间的库仑相互作用也通过α粒子与子核的电荷密度积分给出.计算发现,由于非零角动量带来的禁戒效应和小的α粒子预形成几率,奇Z超重核的α衰变寿命会明显变长.

关键词: α衰变 , 超重核 , 结团模型

Studies on the spin Hamiltonian parameters of vitamin B(12r)

Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The spin Hamiltonian parameters g factors g(i) (i = x,y,z) and the hyperfine structure constants A(i) of vitamin B(12r) have been theoretically studied from the perturbation formulas of these parameters for a Co(2+) (3d(7)) ion with low spin (S = 1/2) in rhombically distorted octahedra. The related crystal-field parameters are determined from the point-charged dipole model and the local structure around Co(2+) in vitamin B(12r). The theoretical spin Hamiltonian parameters are in good agreement with the experimental data. (C) 2008 Elsevier B.V. All rights reserved.

关键词: Electron paramagnetic resonance;Crystal-fields and spin Hamiltonians;Co(2+);Vitamin B(12r);atomic screening constants;electron-paramagnetic-res;scf functions;crystal;spectra;ions;systems;field