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[en] The Office of Fusion Energy of the U.S. Department of Energy convened a workshop in April 1983 to review the needs for copper and copper alloys in fusion device applications. The adequacy of the data base on these materials was examined, and recommendations were developed for experimental programs needed to fill identified data gaps. The workshop results are available in a conference proceedings. (orig.)
[en] Highlights: • Co-doping of Ni-V or Ni-Cr with smaller content could improve the thermal stability of barrierless Cu alloy film. • The relationship between the cluster ratio and the effective distortion of Cu lattices was established. • The stable solid solution cluster-plus-glue-atom model was used to design the composition of Cu seed layers.
[en] Volatile treatment of high capacity boiler water with hydrazine and ammonia is studied. Ammonia comes from the decomposition of excess hydrazine injected to treat dissolved oxygen. Ammonia is also injected for the control of pH. To find an effect of such ammonia on the copper alloy, the relations between pH and iron, and ammonia and copper are studied. Since the dependence of corrosion of iron on pH differs from that of copper, a range of pH was selected experimentally to minimize the corrosion rates of both copper and iron. Corrosion rates of various copper alloys are also compared
[en] Highlights: • Nanoporous copper with high specific surface area was fabricated by dealloying method. • Cu-Ti and Cu-Ti-Ni amorphous ribbons are chosen as precursors. • The addition of a minor amount of Ni alter the resulting nanoporous structure in a large extent. • The nanoporous copper exhibits high electrocatalytic activity toward methanol oxidation.
[en] The main features of sigmoidal transients, not only for viscous glide but also for Power-Law Creep are explained in a physical way. Also the experimental data for the average internal stress, (σi), and the mobile dislocation density, ρm, at the inflection point of sigmoidal creep curves for Germanium and Cu-16at%Al are fully described. Finally, the stress and temperature dependence of the total plastic deformation at the inflection point for sigmoidal creep curves in Cu-11.5at%Al are also catered for (Author)
[en] By determination of formability of the cold extruded material with the indicator of the state of stresses /3 and the effective strain, it is possible very accurate determination of the areas of extruded specimen in which the reserve of formability has already been rather exhausted. In the paper formability of a cold forward extruded specimen of copper alloy as a function of the stress field was analyzed. The stress field and effective strain were obtained by the visioplastidty method in several points of the extruded material. These data make possible to determinate regions in extruded material where the possibility of cracks is the greatest. With known values of the stress components it is possible to calculate the indicator of the state of stresses /3 in the individual points of the extruded specimen by means of equation. The results of calculations are shown in the diagram of formability. Key words: formability, bulk metal forming, visioplastidty analysis, copper alloy
[en] A density-functional--based theory is developed for calculation of the total energy and pressure of random substitutional alloys within the Korringa-Kohn-Rostoker coherent-potential approximation. The theory is used to calculate the concentration variation of the equilibrium lattice spacing of α-phase Cu/sub c/Zn/sub 1-c/ alloys. We find, in agreement with experiment, that the variation is almost linear and that it deviates from Vegard's rule
[en] The effects of predeformation on the precipitation processes in a Cu-2.8 Ni-1.4 Si (at.%) alloy were studied using differential scanning calorimetric (DSC), transmission electron microscopy (TEM) and microhardness measurements. The calorimetric curves shows the presence of one exothermic reaction attributed to the formation of d-Ni2Si precipitates in the copper matrix that was confirmed by TEM. In addition it can be observed that the temperature of the maximum of the DSC peak decreases with the increase of the pre-deformation to the aging treatments. The activation energies calculated for the precipitation of d-Ni2Si, by the Kissinger method, were similar to those calculated by an Arrhenius function, from the maximum hardening of the matrix due to aging treatments (saturation of the hardness during isothermal aging). The analysis of the microhardness measurements together with the calorimetric curves and the TEM micrographs confirm, on the one hand, that the formation of the d-Ni2Si phase, during the aging treatments, are responsible for the hardening of the copper matrix, and on the other hand that the deformation prior to the aging treatment partially inhibits the formation of the precipitates.
[es]Los efectos de la deformación previa sobre los procesos de precipitación en una aleación de Cu-2,8 Ni-1,4 Si (at.%) fueron estudiados utilizando calorimetría diferencial de barrido (DSC), microscopía electrónica de transmisión (TEM) y medidas de microdureza. Las curvas calorimétricas muestran la presencia de una reacción exotérmica atribuido a la formación de precipitados de δ-Ni2Si en la matriz de cobre, lo cual fue confirmado mediante TEM. Además, sse puede observar que la temperatura del máximo del pico de DSC decrece con el aumento de la deformación previa a los tratamientos de envejecimiento. Las energías de activación calculadas para la precipitación de δ-Ni2Si, mediante el método de Kissinger, resultaron similares a aquellas calculadas mediante una función de Arrhenius, a partir del máximo de endurecimiento de la matriz debido al tratamiento de envejecimiento (saturación de la dureza durante el envejecimiento isotérmico). El análisis de las medidas de microdureza en conjunto con las curvas calorimétricas y las micrografías TEM permiten corroborar, por una parte que la formación de la fase δ-Ni2Si, durante los tratamientos de envejecimiento, son los responsables del endurecimiento de la matriz de cobre, y por otra que la deformación previa al tratamiento de envejecimiento inhibe parcialmente la formación de los precipitados.