Stability of pseudotwins in D0(3)-type alloys calculated from first principles

作者：Mizuno Masataka^*; Yasuda Hiroyuki Y; Araki Hideki

来源：Acta Materialia, 2016, 109: 82-89.

DOI：10.1016/j.actamat.2016.02.059

• Twinning
• Intermetallics
• Phase stability
• Phase transformation
• First-principles calculations
• Pseudoelasticity

We investigated the stability of pseudotwins in D0(3)-type Fe3Ga, Fe3Al, Fe3Ge, and Fe3Si using first principles calculations. We found that the energy required to introduce pseudotwins is lowest in Fe3Ga. In Fe3Ga, the calculated energy difference between the D0(3) matrix and the pseudotwin agrees well with the experimental value. We explored the energy landscape for transition from the pseudotwin to the D0(3) matrix and found that there is no energy barrier in the recovery process for the alloys studied. This is owing to the decrease in lattice distortions by structural relaxations caused by the difference in the recovery rate between the pseudotwin layers. The twin boundary plays an important role in inducing structural relaxation: the strain recovery becomes slower with increasing distance from the twin boundary. In contrast to the continuous decrease in the shear strain of the pseudotwin layers in Fe3Ga and Fe3Al, the shear strain in Fe3Si and Fe3Ge decreases discontinuously and the twin shear disappears at the transition point. The difference in electronic structures between D0(3) and the pseudotwin layers is discussed.

• 出版日期2016-5-1