JIAO Yuning
,
LIU Qingmin
,
YANG Yuangsheng
,
HU Zhuangqi
,
Institute of Meta] Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaGAO Yunyan
,
JIA Guanglin
,
ZHANG Guozhi
,
QIAO YuanjunNortheast University
,
Shenyang
,
China Manuscript received 12 May
,
1994
金属学报(英文版)
Navier-Stokes equation and Lorentz force equation are used to calculate the fluid field of liquid metal of electromagnetic centrifugal casting (EMCC) in this paper. A field equation is given, which shows the azimuthal velocity closely relates to electrical conductivity, magnetic density, viscosity of liquid metal and radius of casting. The results show that the stationary magnetic field can effectively restrain the fluid flow and the relative velocity between liquid metal and casting mould and the velocity gradient at solid / liquid interface increases with rising magnetic density, which has a great effect on the solidification of liquid metal and crystal growth characteristics.
关键词:
fluid field of liquid metal
,
null
CHEN Daming KANG Mokuang Northwestern Polytechnical University
,
Xi′an
,
ChinaTAN Ruobing Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The microstructure,strength,toughness and fatigue properties of an ultra-high strength steel 40CrMnSiMoVA have been investigated.The so-called meta-bainite,composed of thin re- tained austenite films within or between the bainitic ferrite lathes was found in the steel after isothermally quenched at 300℃ for 1h.In comparison with the martensite structure obtained by isothermally quenching in martensite range,the meta-bainite has more excellent strength and plasticity,lower notch sensitivity,stronger strain harden ability,higher fatigue strength, longer strain or impact fatigue life,slower crack propagation rate and more remarkable overload effect on increasing fatigue life.
关键词:
ultra-high strength steel
,
null
,
null
,
null
MA Zongyi YAO Zhongkai Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
,
null
,
null
,
null
Z. Yang
,
J.P. Li
,
J.X. Zhang
,
G.W.Lorimer
,
J. Robson
,
null
,
null
,
null
,
null
金属学报(英文版)
The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described: cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study are listed in the final section.
关键词:
Magnesium alloys
,
null
,
null
WADSWORTH Jeffrey and FLUSS Michael(Chemistry and Materials Science Directorate
,
Lawrence Livermore National Laboratory
,
Livermore
,
CA 94551)
金属学报(英文版)
The role of the National Laboratories is summarized from the era of post World War II to the present time. The U.S. federal government policy for the National Laboratories and its influence on their materials science infrastructure is reviewed with respect to .determining overall research strategies, various initiatives to interact with industry (especially in recent years),building facilities that serve the nation, and developing leading edge research in the materials sciences. Despite reductions in support for research in the U.S. in recent years, and uncertainties regarding the specific policies for Research &Development (R&D) in the U.S., there are strong roles for materials research at the National Laboratories. These roles will be centered on the abilities of the National Laboratories to field multidisciplinary teams, the use of unique cutting edge facilities, a focus on areas of strength within each of the labs,increased teaming and partnerships, and the selection of motivated research areas. It is hoped that such teaming opportunities will include new alliances with China, in a manner similar, perhaps, to those recently achieved between the U.S. and other countries.
关键词:
: U.S. Materials Science. U.S. National Laboratories and Facilities
,
null
