| Autor: |
Neshpor, V., Fridlender, B., Komozynskii, P., Ostrovskii, E., Kalinina, N. |
| Zdroj: |
Soviet Powder Metallurgy & Metal Ceramics; 1990, Vol. 29 Issue 6, p502-508, 7p |
| Abstrakt: |
The heat conductivity of the two-phase alloys of ZrC-W system increases with an increase of the tungsten content and with increase in temperature. This is caused by the electron contribution to the heat conductivity of the crbide phase. The electrical resistance of these alloys decreases with increase in tungsten content and increases with increase in temperature. At a mass constant of ZrC > 25% the temperature dependence of the electrical resistance of the alloys is nonlinear as a result of slight overlapping of the valency band by the conduction band in the carbide phase. The mean coefficient of thermal expansion ZrC-75% (wt.) W alloy increases with increase in temperature from 5.5·10 in the range 300-600 to 7.05·10 K in the range 300-2300°K. The spectral emission factor ɛ=0.65 mm of the ZrC-W alloys increases with an increase of the zirconium carbide content. With increase in temperature $$\varepsilon _{\lambda _e } $$ decreases for tungsten, zirconium alloy, and alloys with a mass content of W < 40%. For the alloys with a tungsten content of 45-75% $$\varepsilon _{\lambda _e } $$ depends only slightly on temperature. This can be explained by the presence of tungsten carbides in the subsurface layer. The critical wavelength of these carbides (λ=500-600 nm) is close to the wavelength in pyrometric measurements. The fracture tensile stress of the specimens of the alloys with a mass constant of tungsten of 75% increases with increase in temperature as a result of utilization of a certain ductility margin of the brittle material. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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