| Autor: |
Čadek, Josef, Kuchařová, Květa, Zhu, Shijie |
| Zdroj: |
International Journal of Materials Research: Zeitschrift fuer Metallkunde; December 2021, Vol. 95 Issue: 3 p179-184, 6p |
| Abstrakt: |
Creep in copper dispersion-strengthened with fine alumina particles and reinforced with tungsten short fibres is investigated at three temperatures ranging from 923 to 1023 K. It is shown that creep is associated with a true threshold stress decreasing with increasing temperature more strongly than the shear modulus of copper. The true threshold stress in the composite is higher than that in the composite matrix by a factor K, by which the flow stress in the matrix is reduced due to the load transfer. The minimum creep strain rate is found to be lattice diffusion controlled and to depend on the fifth power of applied stress. The values of the apparent activation energy of creep are higher than that of the activation enthalpy of lattice self-diffusion in the composite matrix, which is fully explained in terms of the temperature dependence of the true threshold stress. The values of the apparent stress exponents are higher than the value of the true stress exponent since the true threshold stress is independent of the applied stress. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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