Creep crack growth in phosphorus alloyed oxygen free copper

Creep crack growth (CCG) has been studied in phosphorus-alloyed oxygen-free copper (Cu-OFP) at 22, 75, 175, and 215 °C with compact tension (CT) specimens. At 175 and 215 °C, the cracks grew about 10 mm before final instantaneous failure. In contrast, there was no visible crack growth at 22 and 75 °C. Strongly deformed grains were observed adjacent to the cracks at 175 and 215 °C. Intergranular creep cavities were found around the cracks. At 22 and 75 °C, deformed grains and some cavities as well as microcracks were observed close to the crack tip. l for crack propagation based on creep damage formation has been formulated to interpret the test results. Rupture criteria based on both creep ductility exhaustion and grain boundary cavitation were taken into account. The contribution from the ductility exhaustion to the creep damage dominated at the lower two test temperatures whereas the contribution from grain boundary cavitation at the higher test temperatures. The model can describe the influence of temperature on the observed creep crack propagation. It can also account for the observed cavitation in a qualitative way.