Resoftening and Resistivity Variations in Thermally Deformed Cu-Sn and Cu-Sn-Zn Alloys | ||
| Egyptian Journal of Solids | ||
| Article 16, Volume 23, Issue 2, 2000, Pages 341-353 PDF (159.12 K) | ||
| DOI: 10.21608/ejs.2000.151746 | ||
| Abstract | ||
| Resistometric and tensile characteristics were studied for both Cu-Sn and Cu-Sn-Zn alloys in the temperature range from 573 K to 773 K. Resistivity saturation was found to take place through two annealing stages. The time exponent n for ε-precipitate dissolution during annealing within stage I in Cu- Sn alloy and stages I and II for Cu-Sn-Zn alloy decreased with increasing working temperature. The values of the rate constant K increased with increasing deformation temperature. A softening behaviour was observed at higher stresses and temperatures. This was deduced from both the decreasing values of the strength parameters σy, σσf, χ, Y with increasing temperature and the sharp change in strain hardening at the critical stress σc . Above σc, the second hardening stage behaviour appeared during tensile testing. The results were explained in view of the mode of dislocation interaction with both the lattice defects and the different inclusions existing in the matrix. The associated atomic rearrangement and the formation of deformation twins, thermally activated by 0.24 eV in Cu-Sn alloy and 0.28 eV in Cu-Sn-Zn alloy, were also considered. | ||
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