SFE intrinsic

SFE intrinsic: Stacking Fault Energy, intrinsic
Definition:Intrinsic stacking fault energy, energy stored in intrinsic stacking fault
Explanation:A stacking fault (→SF) is a one or two layer interruption in the stacking sequence of the crystal structure. These interruptions carry certain stacking fault energy (→SFE). SFs have the same two dimensional periodicity (on the xy plane) as the ideal structure. The irregularities introduced by the faults break the periodicity in the third dimensions (z direction) only. For the calculation of the intrinsic SFE, the structure model is obtained by removing one atomic layer from each nine atomic layers stacked with the normal order ABCABCABC. The remaining eight layers, ABCABABC, are then considered as the repeat unit in the z direction. Because of the two dimensional periodicity of the atoms involved in the present calculation can be minimized to one for each layer. Therefore, the supercell includes eight atoms and the intrinsic SF appears one in each supercell [1]. Fig. 1 shows the arrangement of the perfect fcc (111) surface structure and intrinsic SF [2]. The energy caused by this SF is named intrinsic SFE.
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Fig. 1. FCC (111) surface perfect structures (left) and with intrinsic stacking fault (right) [2].
SFB-Link:SF causes SFE which has an influence on the deformation mechanisms.
References:[1] Q.Jin, P.Wang, D.Ding. ASW first principles calculation of the intrinsic and extrinsic stacking fault energies in aluminium[J]. Physics Letters A, 1993, 174: 437-440.
[2] M.Muzyk, Z.Pakiela, K.J.Kurzydlowski. Ab initio calculations of the generalized stacking fault energy in aluminium alloys[J]. Scripta materialia, 2011, 64, 916-918