Chinese Physics Letters
The Rayleigh identity based on a multipole expansion theory is extended to analyze the mechanical properties of electrorheological fluids. Evaluation of the effective dielectric constant is emphasized. The dependence of the shear stress on the shear strain and the shear modulus for chains of particles arranged on a square lattice are presented.
关键词:
M.C. Somani
,
L.P. Karjalainen
金属学报(英文版)
Systematic physical simulation of thermo-mechanical processing routes has been applied on a Gleeble 1500 simulator to four copper alloys (mass %) Cu-0.57Co-0.32Si,
Cu-0.55Cr-0.065P, Cu-0.22Zr-0.035Si and Cu-1.01Ni-0.43Si aimed at clarifying the
influences of processing conditions on their final properties, strength and electrical
conductivity. Flow curves were determined over wide temperature and strain rate
ranges. Hardness was used as a measure of the strength level achieved. High hardness was obtained as using equal amounts (strains 0.5) of cold deformation before
and after the precipitation annealing stage. The maximum values achieved for the
Cu-Co-Si, Cu-Cr-P, Cu-Zr-Si and Cu-Ni-Si alloys were 190, 165, 178 and 193 HV5,
respectively. A thermo-mechanical schedule involving the hot deformation-ageing-cold
deformation stages showed even better results for the Cu-Zr-Si alloy. Consequently,
the processing routes were designed based on simulation test results and wires of 5 and
2mm in diameters have been successfully processed in the industrial scale.
关键词:
copper alloys
,
null
,
null
F. H.(Sam) Froes
,
C. Suryanarayana
,
and D. Mukhopadhyay (Institute for Materials and Advanced Processes (IMAP)
,
University of Idaho
,
Moscow
,
ID 83844-3026
,
USA)C-G. Li(BlM
,
P.O. Box 81
,
Beijing
,
100095
,
P.R. CHINA)K. Brand(On leave from Institut fur Werkstoffwissenshaft
,
Technische Universitst Dresden
,
07062 Dresden
,
Germany
,
at IMAP)
金属学报(英文版)
Mechanical alloying (MA), a solid-state powder processing method, is a "far from equilibrium" synthesis technique which allows development of novel crystal structures and microstructures, leading to enhanced physical and mechanical properties. The ability to synthesize a variety of alloy phases including supersaturated solid solutions, nanocrystalline structures, amorphous phases and intermetallic compounds themselves is discussed. No extension of solubility using MA has been observed in the intermetallics studied. Nanostructured grains were observed in all compositions. Long time milling generally resulted in amorphous phase formation in large part because of the increase in grain boundary energy/mole with reduced grain size; good agreement with the Miedema model for amorphization was obtained in the Al-Fe system. Generally an anneal was required to form the intermetallic after MA; however,intermetallics with a large negative enthalpy of formation were detected in the MA condition. A study of the hot isostatic pressing of γ-TiAl powders produced by MA demonstrated that full density can be achieved at least 400℃ below the normal temperature required for conventional powder, that is 725℃ or below. Nanometered sized grains (≤100nm)were observed after HIP'ing up to 850℃.
关键词:
: Intermetallics
,
null
,
null
Solid State Communications
The Rayleigh identity, based on a multipole expansion, theory is extended to investigate the mechanical properties of an ideal electrorheological fluid which consists of metal particles with insulating outer layer in a dielectric oil. The evaluation of the effective dielectric constant is emphasized. The dependence of the shear stress tau on the shear strain theta and the shear modulus G for chains of particles arranged on a square lattice is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.
关键词:
Modelling and Simulation in Materials Science and Engineering
Using a bond order potential, molecular dynamics simulations have been performed to study the mechanical properties of ultrathin single-walled carbon nanotubes with or without junction under uniaxial tensile loading. The ( 3, 3) armchair and ( 5, 0) zigzag nanotubes have been studied. Topological defects in the junction region influence the mechanical properties of junctions.
关键词:
y-junctions;devices
Solid State Communications
We have extended the Rayleigh identity based on a multipole expansion theory to analyze the mechanical properties of a new type of electrorheological (ER) system that consists of a novel doubly coated particle in silicone oil. The function of the inner conducting layer of the particle has been investigated. From the shear strain (theta) dependence of effective dielectric constant, the dependence of static yield stress (tau(s)) and shear modulus (G) on the applied electric field are presented. Implications for the design of ER fluids are discussed briefly. (C) 2000 Elsevier Science Ltd. All rights reserved.
关键词:
electrorheological fluids;effective dielectric constant;static yield;stress;shear modulus;conductivity;spheres;forces
