Atomistic simulation of the fcc-hcp transition in single-crystal Al under uniaxial loading

The dynamic behavior of the single-crystal Al under [001] uniaxial strain is simulated by classic molecular dynamics. The fcc-hcp structural transition is successfully observed when the loading pressure reaches about 90 GPa, and the reverse transition is also found with hysteresis. The mechanism and morphology evolution of both the forward and backward transitions are analyzed in detail. It is found in the process of the structural transition that the (010) _fcc or (100)_fcc planes transit into (0001)_hcp planes, and the twins of the hep phase along the (112)-plane appear, whose boundaries finally become along the (110)-plane. Besides, we find the twinning (along the (110)_fcc planes) in the hep phase prior to the back transition (hep-fcc). Our simulations show the coexistence of fee and hep phases over a wide range of pressures, and finally, the phase transition is evaluated by using the radial distribution functions.