PHASE TRANSITION AND SPALL BEHAVIOR OF TIN UNDER RAMP WAVE COMPRESSION

Obtaining the dynamic response experimental data of tin under different thermodynamic paths is the basis for in-depth study of its phase transition and damage physical process. The ramp wave compression experiment of tin was carried out by using magnetic driving loading device CQ-4, and the dynamic response data of tin were obtained. The experimental results show that in the loading section, tin undergoes elastic-plastic transformation and β-γ phase transition. The yield strength is about 0.2 GPa, and the phase transition onset pressure decreases from 7.54 GPa to 7.14 GPa with the increase of tin thickness. There is obvious spallation damage in the unloading section. The spallation strength is about 1.1 GPa, which is greatly different from the impact test results under the same loading pressure. The thickness of the spallation is about 0.38 mm. Combined with the multiphase equation of state based on Helmholtz free energy, nonequilibrium phase strain rate model and damage evolution equation, the experimental dynamic process is numerically simulated. The calculation results can well describe the three physical processes of elastic-plastic transformation, phase transition and spallation.