Dynamic Observations of the Course of a Shock-Induced Polymorphic Phase Transition in Antimony

Flash radiographs have been taken which clearly illustrate the formation of both the first and second plastic waves in shocked Sb. The first plastic wave, whose initial pressure and speed are 115 kbar and 3.25 mm/μsec, respectively, is formed in a time much less than 0.2 μsec, the time exposure of the radiograph. However, the second wave builds up gradually to a steady state where the pressure and speed are 135 kbar and 2.9 mm/μsec. At an initial specimen temperature of about 25°C, the time required to complete the phase transformation behind the first plastic wave is determined to be 2–3 μsec.