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When a defect is a pathway to improve stability: a case study of the L12 Co3TM superlattice intrinsic stacking fault
- Zhang, Ying, Li, Jinshan, Wang, William Yi, Li, Peixuan, Tang, Bin, Wang, Jun, Kou, Hongchao, Shang, Shunli, Wang, Yi, Kecskes, Laszlo J., Hui, Xidong, Feng, Qiang, Liu, Zi-Kui
- Journal of materials science 2019 v.54 no.21 pp. 13609-13618
- case studies, chromium, energy, iron, manganese, molybdenum, nickel, phase transition, platinum, rhenium, rhodium, ruthenium, solutes, superalloys, titanium, vanadium, zirconium
- Effect of solutes of transition metals (TM = Cr, Fe, Hf, Mn, Mo, Nb, Ni, Pt, Rh, Ru, Re, Ta, Ti, V, W, Y and Zr) on the local phase transition between the L1₂ and D0₁₉ structures in superlattice intrinsic stacking fault (SISF) of Co₃TM has been investigated. All the models employed herein, i.e. (1) the SISF-containing supercell, (2) the axial nearest-neighbor Ising (ANNI) model, and (3) both the L1₂- and D0₁₉-containing (L1₂ + D0₁₉) supercell, yield the same result regarding the stability of SISF in L1₂-type Co₃TM. In the view of bonding charge density, the atomic and electronic basis of local D0₁₉ phase transition in the SISF fault layers of Co₃TM are revealed. Especially, the negative SISF energy predicted by the L1₂ + D0₁₉ model suggests that both the SISF fault layers (i.e. the local D0₁₉ structure) and the L12 phase of Co₃TM can be stabilized through a coupling interaction between the fault layers and the solutes, paving a pathway to stabilize Co-base superalloys via Co₃TM precipitate. Moreover, the consist results of ESISF via the ANNI model with the classical SISF-supercell method utilized in first-principles calculations supports the approach to efficiently distinguish various planar faults and predict their corresponding energies, such as SISF, superlattice intrinsic stacking fault, anti-phase boundaries, and so on.