Insight into γ-Ni/γ'-Ni 3 Al interfacial energy affected by alloying elements

Journal Article · Wed Nov 01 00:00:00 EDT 2017 · Materials & Design

DOI:https://doi.org/10.1016/j.matdes.2017.07.028· OSTI ID:1463866

Liu, Xuan L. ^[1]; Shang, Shun-Li  ^[1]; Hu, Yong-Jie ^[1]; Wang, Yi ^[1]; Du, Yong ^[2]; Liu, Zi-Kui ^[1]

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1. The Pennsylvania State University, University Park, PA (United States). Department of Materials Science and Engineering
2. Central South University, Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy

Interfacial energy (σ_γ/γ')oftheγ-Ni/γ'-Ni₃Al interface is critical to understand and design Ni-based superalloys.In the present work, a first-principles methodologywith constrained relaxationshas been used to studythe effectof dilute alloying element (X) on σ_γ/γ' of the (100) coherent interface, where the sixteen X's include Al, Co, Cr, Fe,Hf, Mo, Nb, Pd, Pt, Re, Ru, Ta, Ti, W, Y, and Zr. σ_γ/γ' =19mJ/m² has been predicted for the unalloyed γ/γ' interface,agreeing well with the previous estimations. It is found that the σγ/γ' value is the lowest when alloying element isin γ-Ni, while the addition to γ'-Ni₃Al increases σγ/γ' due mainly to the in-plane lattice expansion. Specifically,our calculations show that alloying elements Mo, W, and Re have the largest effect on the σ_γ/γ' value by decreas-ing it to 4–5mJ/m2when partitioned to γ-Ni; Ru and Pt are shown to increase greatly the σγ/γ'value up to 25–28 mJ/m² when partitioned to γ-Ni; all ternary additions substituting for Ni in γ'-Ni₃Al increase σ_γ/γ' except for Pt; and for Ti and Ta, which segregate strongly to γ'-Ni₃Al and substitute for Al, the σ_γ/γ' values increase to 32 and 35 mJ/m², respectively.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)
• DOE Contract Number: FE0024056; AC02-05CH11231
• OSTI ID: 1463866
• Journal Information: Materials & Design, Vol. 133, Issue C; ISSN 0264-1275
• Publisher: Elsevier
• Country of Publication: United States
• Language: English