The warm-prestressing effect in silicon

Four-point bend experiments are reported in which precracked silicon specimens were subjected to a high-temperature prestress, then tested at room temperature. An increase in the room temperature fracture stress was found; the effect increases with increasing prestressing temperature. These results are interpreted in terms of a model based on dislocation dynamics near a crack; a good fit to the experimental results is found. The model is also used to predict the results of other “warm-prestressing” experiments.