V.M.Kuznetsov
,
G.E.Rudenskii
,
R.I.Kadyrov and P.Kaminskii (The Institute of Strength Physics and Material Science
,
Russian Academy of Sciences
,
Siberian Branch. Academicheskii av. 2/1
,
634048 Tomsk
,
Russia)
材料科学技术（英文）
A model of binding forces in metals and alloys, based on the density functional theory and accounted effects of the many-body interactions, was proposed. The developed method can be easily applied for study of metals and alloys by the molecular dynamics simulation. The potentials of interatomic interactions have been found by the proposed method and applied for calculations of equation of state, elastic moduli and phonon dispersion in metals Ni, Al, alloys NiAl and Ni3Al. Results of the calculations are in good agreement with known experimental data both for pure metals and alloys.
关键词:
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:
Science
The selection of a structural material requires a compromise between strength and ductility. The material properties will then be set by the choice of alloy composition and microstructure during synthesis and processing, although the requirements may change during service life. Materials design strategies that allow for a recoverable tuning of the mechanical properties would thus be desirable, either in response to external control signals or in the form of a spontaneous adaptation, for instance in self-healing. We have designed a material that has a hybrid nanostructure consisting of a strong metal backbone that is interpenetrated by an electrolyte as the second component. By polarizing the internal interface via an applied electric potential, we accomplish fast and repeatable tuning of yield strength, flow stress, and ductility. The concept allows the user to select, for instance, a soft and ductile state for processing and a high-strength state for service as a structural material.
关键词:
crystal plasticity;surface stress;deformation;metals;strain;adsorption;behavior;gold;au
Applied Physics Letters
A bulk nanograined Cu sample embedded with nanoscale twins is produced by means of dynamic plastic deformation at cryogenic temperatures. It exhibits a tensile yield strength of 610 MPa and an electrical conductivity of 95% IACS at room temperature. The unique combination of a high strength and a high conductivity is primarily attributed to the presence of a considerable amount of nanoscale twins which strengthen the material significantly while having a negligible influence on electrical conductivity. (C) 2007 American Institute of Physics.
关键词:
nanocrystalline cu;tensile properties;grain-boundaries;metals;dislocations;resistivity;copper
Applied Physics Letters
We report high strength reliability under tension of a bulk metallic glass (BMG), demonstrated by its high uniformity in strength found over a statistically significant number of specimens, despite the fact that the samples all showed no macroscopic plasticity. Weibull statistical analysis showed that the Weibull modulus of the material is 36.5, which is much higher than the values of more typical brittle materials, further confirming BMGs' high reliability [Appl. Mech. Rev. 5, 449 (1952)]. (c) 2008 American Institute of Physics.
关键词:
plasticity;alloys;temperature;brittleness;estimators;fracture;stress
W.H.Tian
,
C.K.Yan
,
M.Nemoto
金属学报(英文版)
Transmission electron microscopy(TEM) observations were carried out for examining the precipitation behavior in a Cu-Sn-Zn-P lead frame material.TEM observations revealed that the precipitate is hexagonal Ni5P2 and the orientation relationship between the Cu matrix and Ni5P2 precipitate is (111)fcc//(0001)hcp,[101]fcc//[1120]hcp,where the suffix fcc denotes the Cu matrix and hcp denotes the hexagonal Ni5P2 precipitate.The Ni5P2 precipitate is ovoidal in shape at the beginning of aging at lower temperature.By prolonging the aging time or increasing the aging temperature,Ni5P2 precipitate grows and shows a rod-like shape.The Ni added Cu based lead frame material has a comparative mechanical properties with that of TAMAC15 which has been developed and used in electrical industry.
关键词:
lead frame materials
,
null
,
null
