Mechanisms of hot-isostatic pressing

The hot-isostatic pressing of lead, tin and PMMA has been studied, using a rig which enables continuous measurement of density during a test. For the range of experimental conditions used, the dominant mechanisms of densification are plasticity and creep. We found large discrepancies between the data and previous models for these mechanisms. We present improved models, which, while still approximate, include new physical ideas and give a better description of the experiments.