Sound emission during crystallization of undercooled liquid germanium

Abstract

Liquid Ge which had been fluxed in dehydrated B2O3 was allowed to cool below Tm in a well controlled environment. The cooling rate was 6 °C/min. It always crystallized to the diamond cubic phase and the resulting grain size decreased with increasing undercooling. A maximum undercooling of 342 °C was recorded. It was found that sound was emitted during crystallization whenever the undercooling was ≳258 °C for a ∼7-mm-diam specimen. It was also determined that cracks were the source of the sound.