Structure Phase Transformation And Micro-mechanism Of Iron Under Shock Wave Compression

The shock-induced phase transformation and micro-mechanism of single crystal iron from the body-centered cubic phase to hexagonal close-paced phase have been investigated by means of molecular dynamics (MD) simulation, Voter-Chen EAM potential has been used to study the shock-induced phase transformation of iron. By analyzing the moving history of atoms under shock wave compression, the results show that the phase transformation mechanism contains two steps: the compression and the shift courses, respectively. The slip planes have been observed only at some special{011} planes under shock loading. In addition, a nanovoid is settled in the center of the sample to show the effect of defect on the phase transformation, and the results show that the void doesn't change the phase transformation mechanism, but reduces the threshold of pressure and accelerates the nucleation speed of the phase transformation. Also, the void changes the phase transformation nucleation sites, and yields a lot of atoms with amorphous structure around the void. The effect of void is further shown in the particle velocity profile by the production of a lot of "hot spot", which leads to the lower particle velocity in the defective iron.