fcc-to-hcp transformation: A first-principles investigation

A distortion model for the fcc{→}hcp transformation is introduced. It predicts an orientational relationship between parent and daughter phases which is very different from that implied by the Shoji-Nishyiama model. By means of first-principles total-energy calculations, we investigate this pressure-induced transformation in Al and compare the energy barriers along the reconstructional routes implied by both models. We conclude that, from the energetic point of view, both models are equally favorable.