X.G. Yang
,
K. Y. Shu
,
X.B. Zhang
,
Y.Q. Lei and Q.D. Wang(Department of Materials Science and Engineering
,
Zhejiang University
,
Hangzhou 310027
,
China)W. K. Zhang(College of Applied Chemistry
,
Zhejiang University of Technology
,
Hangzhou 310014
,
China)G.L. Lu(Centre of Analysis and Mesurement
,
Hangzhou University
,
Hangzhou 310028
,
China)
金属学报(英文版)
The effect of La alloying on the crystalline characteristics, electrochemical capacity and activity of AB2 type Zr-Cr-Ni hydride electrodes was investigated. It was found that La alloying was able to shorten the activating process from 15 cycles of La-free alloy to 2 cycles, and that the main phase shifts from C14 to C15 by XRD analysis. It may be attributed to the modification of surface chemical states and change in internal microstructures. However, the cycling stability was also found to degrade severely for La-containing hydride electrode because of the collapse of its distorted lattice.
关键词:
Zr-Cr-Ni hydrogen storage alloy
,
null
,
null
Zhaoyang ZENG
,
Lide ZHANG
,
Xiaohong YAN
材料科学技术（英文）
Ballistic transport of Q1D electrons through multiple magnetic barriers is investigated. It is shown that ballistic conductance peaks disappear progressively with the increase of the oscillation frequency of the confining parabolic potential.
关键词:
Andrej Atrens
材料科学技术（英文）
Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.
关键词:
Stress corrosion cracking
,
null
,
null
LIU Guoquan Department of Materials Science and Engineering
,
University of Science and Technology Beijing
,
100083
,
China.
材料科学技术（英文）
Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.
关键词:
stereology
,
null
,
null
,
null
闵凡启
,
高立福
,
卢爱凤
,
王彦国
,
郭丽波
,
李国平
物理测试
doi:10.13228/j.boyuan.issn1001-0777.20150105
针对Q690D钢焊接后出现裂纹的现象,采用化学分析仪、金相显微镜、扫描电子显微镜对钢板的化学成分、金相组织、断口形貌及夹杂物等进行了系统的观察与分析.结果表明:材料的化学成分、金相组织、夹杂物等均在产品质量标准之内,焊接后出现裂纹的主要原因是焊接工艺不规范而导致的材料延迟性脆性开裂.为此制订了合理的焊接工艺规程,通过加强预热、焊后缓冷、优化焊接工艺参数、多道次焊接、焊后消氢处理等措施,有效地避免了焊接裂纹的出现.
关键词:
Q690D钢
,
焊接裂纹
,
延迟性脆性开裂
Materials Science & Engineering C-Biomimetic Materials Sensors and Systems
Bamboo, one of the strongest natural structural composite materials, has many distinguishing features. It has been found that its reinforcement unit, hollow, multilayered and spirally-wound bast fiber, plays an extremely important role in its mechanical behavior. In the present work, on the basis of the study on bamboo bast fiber and wood tracheid, a biomimetic model of the reinforcing element, composed of two layers of helically wound fiber, was suggested. To detect the structural characteristics of such a microstructure, four types of macro fiber specimens made of engineering composites were employed: axially aligned solid and hollow cylinders, and single- and double-helical hollow cylinders. These specimens were subjected to several possible loadings, and the experimental results reveal that only the double-helical structural unit possesses the optimum comprehensive mechanical properties. An interlaminar transition zone model imitating bamboo bast fiber was proposed and was verified by engineering composite materials. In our work, the transition zone can increase the interlaminar shear strength of the composite materials by about 15%. These biomimetic structural models can be applied in the design and manufacture of engineering composite materials.
关键词:
bamboo;bast fiber;biomimetics;engineering composites
薛宪营
,
刘奉家
,
秦军
,
赵虎
钢铁
研究了Q345D低合金高强度中厚板冲击功、侧膨胀率和断面纤维率与温度之间的关系,并利用Boltzmann函数拟合法对不同厚度Q345D中厚板的韧脆转变温度进行了界定。结果表明：拟合所得到的韧脆转变温度各不相同,而且厚规格试样的韧脆转变温度低于薄规格试样的韧脆转变温度。经过优化Q345D连铸坯的连铸和控轧工艺,使Q345D低温韧性有了大幅度提高。
关键词:
Q345D
,
韧脆转变温度
,
Boltzmann函数
,
拟合
董现春
,
张熹
,
陈延清
,
许良红
机械工程材料
分别采用低强匹配的GHS-60焊丝和高强匹配的GHS-70焊丝进行Q550D贝氏体高强钢板的混合气体保护焊接试验，对焊接接头进行了斜Y裂纹敏感性试验、焊后520℃×1.5 h热处理试验，通过金相分析、拉伸试验、冲击试验等评价了不同强度匹配焊丝对焊接接头性能的影响。结果表明：采用GHS-60焊丝时不需要预热便可避免冷裂纹的产生，采用GHS-70焊丝时预热温度在80℃以上才可避免冷裂纹的产生；两种强度匹配的焊接接头力学性能良好，焊后热处理对热影响区和母材的性能没有不利影响，但使焊缝中心韧性有所降低；建议使用低强匹配。
关键词:
Q550D贝氏体高强钢板
,
混合气体保护焊
,
强度匹配
