Abstract
Cu‒1.7 vol.%SiO2 bicrystals having [001] twist boundaries with different misorientation angles were tensile tested at various temperatures above 473 K under various strain rates between 4.17 × 10−5 and 4.17 × 10−3s−1. Intermediate-temperature embrittlement was observed in all the strain rates irrespective of the misorientation. As the misorientation became smaller, the intermediate-temperature embrittlement became clearer and sharper. The temperature of the elongation minimum tended to increase with increase in strain rate. These results could be reasonably understood by considering the competition between the stress concentration around the grain-boundary SiO2 particles caused by grain-boundary sliding and the stress relaxation by Cu‒SiO2 interfacial diffusion.