Eur. Phys. J. B (2013) 86: 188
https://doi.org/10.1140/epjb/e2013-30909-6

Regular Article

Ab initio study of I₂ and T₂ stacking faults in C14 Laves phase MgZn₂

¹ School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, P.R. China
² Department of Physics, Xiangtan University, Hunan Province 411105, P.R. China
³ Light Alloy Net Forming National Engineering Research Center, School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, P.R. China

^a e-mail: tangbiyu@gxu.edu.cn

Received: 7 October 2012
Received in final form: 4 February 2013
Published online: 24 April 2013

Abstract

Based on the synchroshear mechanism, the formation of intrinsic stacking fault I₂ and twin-like stacking fault T₂ in C14 Laves phases has been modeled in detail and the generalised stacking fault energy curve of I₂ and T₂ for C14 Laves phase MgZn₂ has been calculated from first-principles. The results demonstrate that the unstable stacking fault energy of I₂ by synchroshear is still very large, and the stable stacking fault energy of I₂ is higher in comparison with pure Mg implying that the formation of I₂ stacking fault in MgZn₂ is difficult. Starting with the I₂ configuration, the T₂ stacking fault can be formed by an additional synchroshear. The unstable and stable stacking fault energies of T₂ are only slightly larger than those of I₂, implying that the formation of T₂ may be essentially similar to that of I₂. From the obtained generalised stacking fault energy, the relevant deformation mechanism of MgZn₂ is also discussed. Finally, the electronic structure during synchroshear process is further studied.