A model explaining the Rule for Calculating the Break-up Time of homogeneous ductile metals

It was shown in a previous paper⁽¹⁾ that the break-up time of homogenious ductile metals which elongate due to explosions, is equal to the sample's smallest initial dimension (thickness) divided by the velocity V_pl which characterizes the metal. It is attempted to explain this rule by suggesting a break-up mechanism where holes caused by a pile-up of vacancies are formed at the metal surface and gradually increase until breaking it. This model also predicts the existence of a strain rate threshold below which other mechanisms dominate the break-up process. Its validity is supported by experimental evidence which is also presented.