Effect of plastic prestrain magnitude on uniaxial tension creep of copper at elevated temperatures

The effect of prior plastic deformation on creep properties such as minimum creep rate, time to rupture, duration of creep stages, and elongation at 523 and 573 K under uniaxial stress state has been determined for various tensile plastic prestrains. It has been shown that minimum creep rate, and elongation decreased as the amount of plastic prestrain increased. However, this relation was proportional to the plastic predeforma-tion only up to e^p=5%. A little increase of the time to rupture with the increase of plastic predeformation has been observed for specimens tested at higher temperature (573 K) in comparison to nonprestrained material. In the case of lower temperature (523 K) the lifetime decreased significantly with the increase of plastic predeformation. Predeformation also shortened the duration of primary and secondary creep stages for both temperatures considered.