X.H. Cui
,
Q.C. Jiang
,
S.Q. Wang and Z.M. He (School of Materials Science and Engineering
,
Jinn University of Technology
,
Changchun 130025
,
China)
金属学报(英文版)
Compared with conventional cast Cr12Mo V steel and forged Cr12Mo V steels, carbide morphology and properties of modified cast Cr12MoV steels were investigated by performing hardness test, impact test, fracture toughness test, fatigue crack propagation test, metallographic examination and quantitively metallographic analysis. The results indicate that the carbide morphology in modified cast steel is characterized by granular carbide uniformed- distributed, which is different from that of conventional cast steel, but similar to that of forged steel. The impact toughness of modified cast steel is distinctly increased to 12.75J/cm2 from 6.8J/cm2 in the conventional cast steel with networked carbide, because of carbide granulation. Furthermore, The fracture toughness and fatigue - cock-propagation threshoid of modified cast steel are not only higher than that of the conventional cast steel, but also higher than that of the forged steels.
关键词:
carbide
,
null
,
null
,
null
,
null
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
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
Science
Strengthening materials traditionally involves the controlled creation of internal defects and boundaries so as to obstruct dislocation motion. Such strategies invariably compromise ductility, the ability of the material to deform, stretch, or change shape permanently without breaking. Here, we outline an approach to optimize strength and ductility by identifying three essential structural characteristics for boundaries: coherency with surrounding matrix, thermal and mechanical stability, and smallest feature size finer than 100 nanometers. We assess current understanding of strengthening and propose a methodology for engineering coherent, nanoscale internal boundaries, specifically those involving nanoscale twin boundaries. Additionally, we discuss perspectives on strengthening and preserving ductility, along with potential applications for improving failure tolerance, electrical conductivity, and resistance to electromigration.
关键词:
strain-rate sensitivity;stacking-fault energy;nano-scale twins;cu-al;alloys;nanocrystalline metals;mechanical-properties;activation;volume;copper;deformation;behavior
唐郑磊
,
丁健
,
许少普
,
李忠波
,
杨阳
,
康文举
钢铁研究
根据265 mm厚S500Q-Z35钢板的化学成分,评估冷裂敏感性和再热裂倾向,并对钢板进行Z向窗形层状撕裂试验和T型接头模拟件焊接试验,试验未发现裂纹.按美国ASME标准进行焊接工艺评定,可焊接的最大厚度为350 mm.气体保护焊GMAW和手工焊SMAW焊接后母材组织为粒状贝氏体+索氏体+少量铁素体,热影响区靠近母材区域为索氏体组织,近焊缝区为板条马氏体,并有网状析出物,焊缝区组织为针状铁素体+网状、半网状的先共析铁素体.
关键词:
S500Q-Z35
,
焊接
,
裂纹敏感性
,
微观组织
Douxing LI and Hengqiang YE (Laboratory of Atomic imaging of Solids
,
Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
110015
,
China)
材料科学技术（英文）
The present paper summarizes the current status of high resolution electron microscopy (HREM)and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction,subnanometer level analysis, image simulation and image processing.
关键词:
N.V.Ch
,
ra Shekar
,
P.Ch.Sahu
,
K.Govinda Rajan
材料科学技术（英文）
Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.
关键词:
Laser heating
,
null
,
null
,
null
张强
,
许少普
,
李忠波
,
唐郑磊
,
高照海
,
杨阳
钢铁
doi:10.13228/j.boyuan.issn1001-0963.20150135
采用横截面为350mm×2 320 mm的钢坯轧制横截面为100 mm×2 360 mm的Q345E-Z35.在粗轧阶段以高于动态再结晶临界变形量和形状系数l/h≥0.53的条件下,经过不同的终轧温度和返红温度试验,最终确定精轧阶段终轧温度控制在780℃左右,返红温度控制在610℃左右,生产出的钢板具有优异的力学性能和层状撕裂抗性.
关键词:
Q345E-Z35
,
特厚板
,
控轧控冷
