Influence of bubbles on grain growth in ice

Numerical static grain growth simulations of ice with air bubbles as a second phase show a significant drop in grain-growth rate compared to bubble-free ice. The magnitude of this drop in growth rate is dependent on the bubble boundary mobility, the volume fraction of air, the average bubble size and the bubble size distribution. The rate of grain growth decreases at first, as the microstructure evolves towards a steady state. Only then does grain growth follow the expected linear increase of mean grain area with time. In experiments, this decrease in growth rate could erroneously be interpreted as growth with a deviating growth exponent.