EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

This study reports the first experimental evidence of the violation of the classical law for grain growth in twinned boron carbide ceramics. Grain-growth kinetics is drastically dependent on the presence of twin steps at the grain boundaries in B4C ceramics sintered by spark plasma sintering. The conjunction of high temperature gradients with large compressive stress when a pulse electric current passes through the ceramic powders gives rise to an intense twinning–detwinning formation. These forming steps at the grain boundaries change the grain mobility drastically. Therefore, a new ‘exotic’ law for grain-growth kinetics is found and validated at different temperatures and dwell times. The time dependence of the grain size is proved to follow one law which has the same functional form as the Bose-Einstein distribution law.