176 / 2023-04-15 13:06:48

The deviation of the dynamic structure from the equilibrium phase diagram in shock-released bismuth due to metastable formation

高压物理与材料科学 > 相变与机制-海报

It is well known that the dynamic structure may deviate from the equilibrium phase diagram due to the finite period of phase transformation compared to the loading/unloading processes. Normally, the phase boundaries are shifted considering the phase transformation kinetics. However, abnormal case may arise if metastable phase interferes with the equilibrium phase transformation pathway. This special case is investigated in the shock release period of bismuth using a time resolved X-ray diffraction technique. The Bi-V to the metastable Bi-IV, instead of the Bi-V to the thermodynamic stable Bi-III, was observed, revealing a long nucleation time of about 5.1 ns. This observation demonstrates the importance of the formation of the transient metastable phases, which is able to change the phase transformation pathway in a dynamic process.