YI Hailong
,
DU Linxiu
,
WANG Guodong
,
LIU Xianghua
钢铁研究学报(英文版)
A hotrolled steel with high yield strength of 700 MPa, good elongation of about 20% and low ductilebrittle transition temperature (DBTT) lower than -70 ℃ has been developed in laboratory. The results show that adopting finishing rolling temperature of around 800 ℃ is rational, and coiling temperature is between 400 and 500 ℃. The strength of developed 700 MPa hotrolled high strength steel is derived from the cumulative contribution of fine grain size, dislocation hardening and precipitation hardening. The fine grain strengthening and precipitation hardening are the dominant factors responsible for such high strength, and good elongation and toughness are predominantly due to fine grain ferrite.
关键词:
high strength steel;precipitation hardening;ductilebrittle transition temperature;fine grain strengthening
王丽
,
吴希文
,
张晨鼎
,
张通
,
简丽
,
武朝军
,
周涛
稀土
doi:10.3969/j.issn.1004-0277.1999.02.003
采用湿渣法研究了0℃时碘化钇(YI3)-乌洛托品氢碘酸盐(C6H12N4.HI)-水(H2O)的三元体系相平衡,绘制了该体系的等温溶解度相图,相图分析结果表明,该体系中有组成为YI3.C6H12N4.HI.14H2O的配合物生成,对所得配合物进行了化学分析、X-射线粉末衍射、红外光谱、差热-热重分析,测定了其密度、晶体轴性,确定了配合物结构中的配位关系.
关键词:
相平衡
,
碘化钇
,
乌洛托品氢碘酸盐
,
配合物
Physical Review B
Longitudinal electron transport is investigated for a long-period semiconductor superlattice in the presence of a magnetic field applied along the growth direction of the superlattice. It is shown that the longitudinal magnetoresistance exhibits a complicated dependence on the magnetic-field strength. In contrast with the conventional Shubnikov-de Haas oscillations, the magnetoresistance shows periodic oscillations only in the region of low reciprocal magnetic field.
关键词:
magnetoresistance
F.M.Chu David P.Pope Dept.of Materials Science and Engineering
,
University of Pennsylvania
,
Philadelphia
,
PA 19104
,
USA
材料科学技术（英文）
In this paper the geometric description and general theory of mechanical twinning are reviewed, the twins in general lattices and superlattices are summarized, and the kinetic process by which mechanical twins form is revisited. A case study of mechanical twinning of HfV2+Nb, (cubic) Laves phase, is presented and the synchroshear of selected atomic layers is proposed to explain the physical process of twin formation. If the twins form in this way, then long shear vectors and / or atomicshuffles are not really necessary.
关键词:
twin
,
null
,
null
,
null
J.M. Gong
,
S.T. Tu
,
J. Xia and X. Ling (School of Mechanical Engineering
,
Nanjing University of Chemical Technology
,
Nanjing 210009
,
China)
金属学报(英文版)
Creep deformation localization is generally found in structures at high temperamture,typically in weldments. As the heat affected zone (HAZ) in a weldment is very narrow, deformation in HAZ region can hardly be measured by conventional displacement gauge. A new method for measuring long-term local creep deformation was developed by quartz optical fiber and technique of digital image analysis. The creep deformations of base metal, weld metal and HAZ in weldments are thereby determined with crossweld specimens.
关键词:
creep deformation
,
null
,
null
,
null
材料科学技术（英文）
A new type of long periodic structure has been found in ZrO2-Y2O3 ceramics in annealed states. High resolution electron microscopy (HREM), selected area electron diffraction, and computer simulation have been used to reveal the presence of the long periodic structure. The unit cell of the long periodic structure consists of a cubic ZrO2 unit cell and L1(0)- like phase one.
关键词:
ceramics;electron diffraction;electron microscopy;crystal structure;microstructure
Jiancun RAO
,
Yu ZHOU
,
Douxing LI
材料科学技术（英文）
A new type of long periodic structure has been found in ZrO2-Y2O3 ceramics in annealed states. High resolution electron microscopy (HREM), selected area electron diffraction, and computer simulation have been used to reveal the presence of the long periodic structure. The unit cell of the long periodic structure consists of a cubic ZrO2 unit cell and L10- like phase one.
关键词:
Ceramics
,
null
,
null
,
null
,
null
Applied Physics Letters
The dipole configuration of relaxor ferroelectrics (RFs) is investigated by numerically solving the time-dependent Ginzburg-Landau equation based on the dipole defect model. The domain structure of RFs is revealed to consist of dipole ordered clusters embedded in the paraelectric matrix. We demonstrate that the role of long-range elastic energy in RFs is much less important than in normal ferroelectrics, although the shape of the dipole clusters depends on the elastic energy. Based on the numerical results, a phase diagram of temperature-defect density for RFs is constructed, which identifies four distinct phase regimes. (c) 2006 American Institute of Physics.
关键词:
monte-carlo-simulation;dielectric-properties;computer-simulation;domain formation;defects;field;model;glass
Physical Review A
This paper investigates the motion of a Brownian particle experiencing both a friction (biased) force and a randomly fluctuating force with a long-time-correlation function C(f)(t) approximately t(-B), 0 < beta < 1, 1 < beta < 2, and beta = 1, instead of a Dirac delta-function. The generalized Langevin equation and Fokker-Planck equation and corresponding solution are presented. It is shown that when 0 < beta < 1 or 1 < beta < 2, the diffusion motion of the Brownian particle is the anomalous diffusion that is related to fractal Brownian motion (FBM). But when beta = 1 the diffusion motion is anomalous diffusion with no connection to FBM. The effects of friction retardation result in a probability density function for finding the particle at displacement X at time t that depends on the initial value of velocity of the particle. The approach in this paper may provide a systematic method for the study of particles diffusing in fractal media.
关键词:
disordered media;brownian-motion
