Papers by Keyword: Cu Alloy

Abstract: This article produced porous materials by using a simple and easy method which is a powder metallurgy. This search studying an experimental fulfillment on the thermal conductivity, apparent porosity, and Diametrical Strength of porous copper-zinc manufactured by the convert to carbon since firing process and combined with the oxygen cause to CO2 gas that rises up to air and leaves the number of pores. the basic metals are Cu and Zn pure powder metals with a different ratio (10-20-30)% of natural leaves especially palm leaves which is widely found in our natures, Cu fine powder (220 µm) has purity 99.5% as a matrix material to prepared composite material with ratio 80% of material total weight, 500g, Zn fine powder added as 20% from material total weight, the Zn metallic powder has purity 99.5%. The Zn powders have size particle less than200 𝜇m. Grounded palm leaves were cut to small parts then milled by using electrical mortar to get a fine powder which have a green size (less than 0.75 𝜇m) which result by sieving instruments. The results show various values in each test. In physical testing the apparent porosity from pure \Cu-Zn has 0.11%,10%0.187%,20% 0.22,30%0.32%,where the higher value for samples of palm leaves which has presence in a higher value in 30% of palm leaves, the others tests in thermal conductivity and diametric strength, in thermal conductivity have(5 W/m.k for pure material, in 10% 0.65 W/m.k, in20% 0.38 W/m.k,in 30% 0.2 W/m.k)for Cu-Zn-P.L composites these investigations show a decreasing ingredients especially in 30%, which have the lower value with the same effect in Diametrical Strength in pure samples has 25Mpa,in 10% has 10 Mpa, in 20%6Mpa,in30% 2.5Mpa.Generally the Optimum properties of Cu-Zn-P.L additives are attained with least porosity content. The existences of porosity decline the Diametrical Strength, thermal conductivity. Thus the aim of this study was to create porous composites metal MMC with has high attractive as an insulating material, and porous composites with natural additives.

Abstract: In this study, Cu films doped with different Sn concentrations from 0.6-1.4 at.% were prepared by magnetron co-sputtering. The electrical resistivities and microstructures of Cu (Sn) films after annealings were investigated. The results showed that a sharp increase of the resistivity of Cu (1.4 at.% Sn) and Cu (1.1 at.% Sn) films were found after annealing above at 500°C. The existence of 0.6 at.% Sn in the Cu film is in solid solution state. A minimum electrical resistivity value of ~3.2μΩ•cm was obtained after annealing at 600°C for 1h . Even after a annealing at 700°C, the Cu/Si interface of Cu (0.6 at.% Sn) film still remained sharp without any Cu-Si and Cu-Sn compounds. The results confirmed that the lower resistivity and higher stability of Cu films can be achieved by strictly control of the doping concentrations and the existing state (solid solution without compounds and precipitates) of Sn element.

Abstract: Aging solution-treated Cu-Ti alloys in a hydrogen atmosphere significantly improved their electrical conductivity without degradation of the mechanical strength, compared to conventionally aged alloys. In this study, the influence of prior deformation on the mechanical and electrical properties of Cu-4.2 at.% Ti alloys aged in a hydrogen atmosphere was examined. The Vickers hardness of the solution-treated specimen increased from 127 kgf/mm2 to 265 kgf/mm2 by aging at 673 K for 180 h in a hydrogen atmosphere of 0.8 MPa, while that of the deformed specimen achieved a maximum of approximately 280 kgf/mm2 by aging for 100 h in the same atmosphere. Prior deformation resulted in a more rapid increase in conductivity during aging than that without deformation. The conductivity at the peak-hardness of the deformed specimen was 22% IACS (International Annealed Copper Standard), which exceeded that for the solution-treated specimen. Thus, prior deformation assisted in a significant improvement of the mechanical and electrical properties during aging in a hydrogen atmosphere.

Abstract: Alloys displaying positive enthalpy of mixing demix below a critical temperature. In Co-Cu and related ternaries the miscibility gap is metastable, i.e. it occurs at temperatures lower than the liquidus. In order to study the liquid phase separation high melt undercooling is necessary. This was obtained via rapid solidification techniques using melt spinning and casting in moulding devices, as well as high temperature DSC experiments with samples embedded in a flux. Results are given for Co-Cu, Co-Cu-Fe and Co-Cu-Ni systems. Phase diagrams were optimised using the DSC data. The mechanism of phase separation was investigated by comparing samples produced under different cooling conditions. The hierarchy of microstructures obtained was interpreted accounting for the processing technique and the phase diagram. They constitute a database useful for the interpretation of the thermal history of samples processed in microgravity.

Abstract: By associating texture determinations and strains measurements by neutron diffraction, the elastoplastic behaviours of families of crystallites with the same crystallographic orientations were characterized in situ in a brass and a bronze alloys under uniaxial loading. The polycrystalline orientation analysis method proposed here allows an intermediate approach between a “local” (intragranular) and a “global” characterization, within the bulk of massive samples.

Abstract: The effect of the amount of dispersoids on softening behavior and recrystallized microstructure of Cu-Fe-P alloy was examined by the extracted residue analysis method. The degrees of contribution of larger particles (larger than 1μm in an average diameter) and smaller ones (less than 0.1μm) to the softening behavior were considered in the quantitative aspect, respectively. It was found that the change of the order of 10-1mass% in the amounts of both particles has a great effect on softening behavior. The difference in the amount of fine particles changes recrystallized grain size distributions at similar hardness. In the specimen with a small amount of fine particles, coarse grains and wide distribution of grain size were observed after annealing. As a result, it was revealed that fine and homogeneous recrystallized microstructure was obtained due to just 0.35mass% of fine partcles, even if the amount of large particles increased.