LI Hui Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaLIU Xiang Northeast Institute of Technology
,
Shenyang
,
ChinaGUO Jianting HU Zhuangqi Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Associate Professor
,
Institute of Metall Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
By means of nonstoichiometry,rapid solidification and adequate boron addition,the tensile strength and bending resistance of Ni_3Al has been improved.When adding 0.52 to 1.37 at.-% B into Ni_3Al,which has the beneficial effect on the ductility.If boron addition is too high, there are coarse Ni_(23)B_6 particles and NiB_(12) phases found at the grain boundaries.Boron modification in Ni_3Al promotes the ordering in the region near grain boundaries.The grain boundary of boron free Ni_3Al is a large angle one,but turns into a small angle grain bound- ary with sub-grains of dislocation characteristics when the boron content in Ni_3Al reaches 1.37 at.-%.
关键词:
intermetallic compound
,
null
,
null
,
null
WAGENDRISTEL A Viena Technical Univessity
,
AustriaHUANG Rongfang Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaBANGERT H YANG Xia WU Lihang WANG Haifeng PANGRATZ H SKALICKY P Viena Technical University
,
Austria Associate Professor
,
Institute of Metall Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The microstructure of Ti/TiN multilayer film was studied.It was shown by trans- mission electron microscopy of cross-sectional sample and respective secondary neutrals mass-spectroscopy depth profiling that the film has a periodic alternate multilayered structure:substrate /FeTi/Ti/Ti_2N/TiN/Ti_2N/Ti/Ti_2N/TiN...Ti/Ti_2N/TiN,where FeTi and Ti_2N were the transition layers formed during ion plating.Cross-sectional fracture surface of indentation samples had been obtained and studied with scanning electron microscopy.It was shown that the multilayer film deformed during indentation, formed an indentation pit and a pile-up of materials around the indentation pit.As the applied load increased deformation region extended beyond the film/substratc interface and into the substrate,the interlayer crack in the film and hole formation at the film /substrate interface were initiated.It is also shown that the multilayered Ti/TiN film offered better toughness in comparison with single layer TiN film.
关键词:
multilayer Ti-N film
,
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