Atomistic simulation of nanovoid-induced structural transition in shocked iron

It is well known that the structural transition can cause an abrupt change of material’s physical and mechanical characters. One of the best studied examples is the structural transition in iron. Under the high pressure of about 13 GPa, iron can undergo a representative martensitic transformation [1]. For this reason, the structural transition in iron has been an interesting subject in high pressure research, including experimental and theoretical investigations [2, 3, 4, 5, 6, 7, 8, 9, 10]. However, the phase transition is a typical multi-scale problem from the discrete microstructure to the macroscopic change. The classical theoretical studies encounter many difficulties in understanding the nature of the phase transition. With the rapid development of the computer capability, the bcc→hcp transition in iron under shock compression was successfully observed at the atomistic level by Kadau et al. with molecular dynamics (MD) simulations [8] in 2002; later, the results were confirmed by Kalantar et al. via ultra fast in situ x-ray diffraction studies of iron [10]; Here, we perform MD simulations on the the shock-induced bcc-to-hcp transition in iron containing a nanovoid.