材料期刊网

OPTIMAL DESIGN PROCEDURE BASED ON VISCOPLASTIC MATERIAL BEHAVIOUR

J. Brnic , G. Turkalj and M. Canadija Faculty of Engineering , Vukovarska 58 , 51000 Rijeka , Croatia

金属学报(英文版)

The optimization problems belong to the family of the most important engineering problems. The objective of this paper is to proposed a very efficient numerical algo- rithm which is involved in an optimal design procedure in the field of viscoplasticity phenomena. Because of the complexity of design procedure, particularly in the field of viscoplas- ticity, the finite element method is used. This method provides a good structural discretization and very efficient mathematical describing of time-rate effects. Accord- ing to the design specifications, which will dictate a limiting design strain, using the proposed algorithm, the design life of the considered structure will be covered. For the justification of the proposed method an example is presented. On the basis of specifications data and environment conditions, an operating pressure of a pressure vessel is obtained.

关键词: optimal design , null , null , null

ALLOYING BEHAVIOUR OF Ca IN STEEL 58CrV

LU Feng CAO Fengyu LI Chengji University of Science and Technology Beijing , Beijing , ChinaZHANG Yongxiang CHEN Yonggang Beijing Institute of Machine Tools , Beijing , China Faculty of Metallograph , University of Science and technology Beijing , Beijing 100083 , China

金属学报(英文版)

Effect of Ca on hardenability and CCT diagram of steel 58CrV has been investigated by means of end-quenching and thermal expansion.An addition of 0.006 wt-%Ca to the steel may improve the hardenability,reduce the critical cooling rate of transformation of pearlite or bainite under continuous cooling and increase the M_s.AES analysis showed that Ca segre- gates markedly along austenitie grain boundaries,and accelecrates the segregation of C,Cr and Si.It is believed that besides towards deoxidizing and desulphurizing as well as improving sulphide morphology,a trace of Ca in steel 58CrV behaves towards microalloying.

关键词: Ca , null , null , null

Coalescence between Cu(57) and Cu(58) clusters at a room temperature: molecular dynamics simulations

Chinese Physics B

Three coalescence processes of Cu(57)-Cu(57), Cu(57)-Cu(58), and Cu(58)-Cu(58) clusters at 300 K are investigated by employing molecular dynamics simulations. According to the evolutions of mean square displacement and local atom packing, the coalescence process can be separated into three stages including an approaching stage, a coalescing stage, and a coalesced stage. The simulations show that the coalescence processes and the formed products are sensitive to the respective initial structures of, and the relative configuration between, the two coalescing icosahedron-based clusters.

关键词: cluster;molecular dynamics;computer simulation;surface;electronic-properties;structural-changes;melting behaviors;gold;copper;particles;cu

Bi Layer Formation at the Anode Interface in Cu/Sn-58Bi/Cu Solder Joints with High Current Density

Hongwen He

材料科学技术（英文）

Bi layer formation in Cu/Sn{58Bi/Cu solder joints was investigated with different current densities and solder thickness. Uniform and continuous Bi layers were formed at the anode interface which indicated that Bi was the main diffusing species migrating from the cathode to the anode. The electromigration force and Joule heating took on the main driving forces for Bi diffusion and migration. In addition, two appearance types of  Bi layers, planar-type and groove-type, were found during current stressing. The morphology and thickness of Bi layers were affected by current density and current stressing time.

关键词: Bi layer formation , null , null , null

卫58块油井结垢腐蚀因素分析及防护措施

安思彤 , 陈秀玲 , 关建庆 , 王正坤

腐蚀与防护 doi:10.11973/fsyfh-201508021

油田开发到中后期,含水率高,油井结垢及垢下腐蚀加重.通过结垢腐蚀原因分析,规律研究,制定防护方案,有针对性地解决油井结垢及垢下腐蚀问题.并以中原油田卫58块为例,通过投加缓蚀阻垢剂及加药工艺优化控制结垢腐蚀问题.现场监测表明,油井结垢腐蚀程度明显减弱,结垢腐蚀速率降低60％以上,采出液总铁含量降低超过70％,且波动减小.

关键词: 油井 , 结垢 , 垢下腐蚀 , 因素分析 , 防护措施

Ca在58CrV钢中的合金化行为

陆丰 , 曹凤豫 , 李承基 , 张永祥 , 陈永刚

金属学报

本文报道了用端淬法和热膨胀试验研究微量Ca对58CrV钢淬透性和CCT曲线的影响和用Auger能谱(AES)分析断口表面的Ca及其它合金元素含量的结果。表明,微量Ca明显提高钢的淬透性,在连续冷却时降低珠光体转变及贝氏体转变的临界冷却速度,提高Ms点Auger谱分析表明,Ca在奥氏体晶界有十分明显的晶界偏聚,并促进C、Cr、Si的晶界偏聚认为微量Ca除了脱氧去硫和改善硫化物形貌作用外,还有合金化的作用。

关键词: 微量Ca , hardenability , CCT diagram , grain boundary segregation , null

Effects of scratching on corrosion and stress corrosion cracking of Alloy 690TT at 58 degrees C and 330 degrees C

Corrosion Science

Scratched Alloy 690TT were characterized using X-ray stress analysis technique, nano-indentation, SEM, electrochemical and immersion tests. The stresses adjacent to the scratches, which resulted from scratching, were tensile parallel to the scratches and compressive perpendicular to the scratches. In the acidic sodium chloride solution at 58 degrees C, scratching caused E(corr) to shift negatively owing to a transient anodic current accompanied by a larger difference between E(corr) and the potential of zero charge. Pit 330 degrees C in the lead-containing caustic solutions, SCC initiated at the scratch-banks and scratch-beds after 30 days' immersion. Scratched Alloy 69017 exhibited both IGSCC and TGSCC in initiation. (C) 2009 Elsevier Ltd. All rights reserved.

关键词: Nickel;Polarization;Stress corrosion;tribological contact analysis;hard coated surface;stainless-steel;repassivation kinetics;localized corrosion;mechanical analysis;part;i;water;deformation;strain

p+~(58)Ni反应中集体态及转移机制的影响

梁春恬 , 蔡崇海

原子核物理评论

在p+~(58)Ni反应的理论计算中考虑了集体态和转移反应机制,利用大型程序MEND计算了E_(in)≤200 MeV能区6种轻粒子(n,p,a,d,t及~3He)出射的能谱和双微分截面.计算结果与实验数据基本一致;与以前的工作相比,解释了能谱和双微分截面中出现的尖峰,并减小了单粒子态密度修正因子ccg1(v).

关键词: 集体态 , 转移反应 , MEND , 能谱 , 双微分截面

58SiMn高强度钢车削表面完整性的试验研究

罗智文 , 焦黎 , 赵文祥 , 袁美霞 , 王林林 , 王西彬

表面技术 doi:10.16490/j.cnki.issn.1001-3660.2017.01.038

目的 研究58SiMn高强度钢表面完整性评价指标受切削参数影响的变化规律.方法 分别设计单因素和正交试验,采用涂层硬质合金刀具对58SiMn高强度钢进行车削加工试验,通过采集相关数据,分别讨论了切削深度、进给速度和切削速度变化对表面粗糙度、残余应力、显微硬度和表层微观组织变化等方面的影响.结果 进给速度对表面粗糙度的影响最显著,切削速度次之,切削深度的变化对表面粗糙度无直接影响.已加工表面的残余应力随切削速度和进给量的增大而增大.显微硬度随切削深度的增大而减小,随进给量的增大而增大,层深上的显微硬度则呈现先减小后增大的趋势.表层微观组织受切削速度影响不大,未出现明显的相变和晶粒歪曲.结论 降低进给速度是减小工件表面粗糙度最直接有效的方法,提高切削速度并不能使表面粗糙度明显减小.工件表面的轴向和切向残余应力均为拉应力,为提高零件使用性能,应采取相应的措施使之转化为压应力.

关键词: 表面完整性 , 高强度钢 , 表面粗糙度 , 残余应力 , 显微硬度

Mg58Al42储氢合金的制备及其电化学性能

张辉 , 王婷 , 曹中秋 , 张国英

稀有金属材料与工程

采用机械合金化技术制备了Mg58Al42储氢合金并借助于X射线衍射仪、PARM273A和M5210电化学综合测试仪研究了其在不同球磨时间下的物相结构以及放电容量和耐腐蚀等电化学性能. 结果表明:合金粉末经高能球磨后产生了Mg17Al12新相,随着球磨时间的增加,衍射峰的相对强度下降,衍射峰变宽,合金的平均晶粒尺寸降低,内应力增大.合金的放电容量随球磨时间的延长先增加而后则降低,其中球磨20 h时,放电容量最大.合金的动电位极化曲线出现了钝化现象,合金腐蚀电流密度随球磨时间的延长先增大而后降低.合金的交流阻抗谱均由单容抗弧组成,电极反应受合金/电解质溶液界面的电荷迁移所控制.

关键词: 镁基储氢合金 , 电化学性能 , 交流阻抗谱(EIS)