Autor: Yu. V. Vorobiev, Jesús González-Hernández, M. E. Pérez-Ramos, Paul P. Horley, P.Yu. Vorobiev, Alejandro Manzano-Ramírez
Rok vydání: 2003
Předmět:
Zdroj: Inorganic Materials. 39:37-42
ISSN: 0020-1685
DOI: 10.1023/a:1021883001600
Popis: The microstructure of an automobile gear made by the powder metallurgy process was studied using scanning electron microscopy and optical microscopy with further computer analyzing of images. The investigation of the electrical properties of the gear was done employing standard resistivity measurements and analyzed using an original method to determine the local orientation of the electric field. This last method provided us with the distribution of the electric current lines, which clearly reflects the local anisotropy and fractures in the material. We found that the electric resistivity in the specimens studied is extremely sensitive to the porosity of the material. It is shown that none of the existing theories of the electric conductivity of composite materials, including the Maxwell theory and the frequently used “brick model,” are able to explain this supersensitive dependence on porosity. A new approach is developed, taking into account the anisotropic character of the material. The results of this modeling have shown a good agreement with experimental results. The new method of electric field mapping may be recommended for investigation of the other structural materials. The model developed might be useful, in particular, for a discussion of the influence of the pores on their mechanical properties.
Databáze: OpenAIRE
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