Compressive behavior and elastic properties of Ni-based γ/γ’ ternary model superalloys: First-principles calculations and rule of mixtures predications

• Published in: Journal of alloys and compounds 2020-10, Vol.839, p.155661, Article 155661
• Main Authors: Wen, Minru, Xie, Xing, Dong, Huafeng, Lin, Zhiping, Wu, Fugen, Wang, Chong-Yu
• Format: Article
• Language: English
• Subjects: Alloying elements; Charge density; Compressive properties; Compressive strength; Deformation analysis; Density functional theory; Elastic properties; Energy methods; First principles; First-principles calculations; Mechanical properties; Modulus of elasticity; Multilayers; Ni-based ternary model superalloys; Nickel base alloys; Rule of mixtures; Single crystals; Strengthening; Superalloys; Ternary alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.155661

Using a total-energy method based on the density functional theory (DFT), the strengthening effects of Mo, Ta, W, and Re on the ideal uniaxial compressive strength (σICS) and elastic properties of Ni-based single-crystal (NBSC) superalloys were systematically investigated using a model consisting of γ/γ′ multilayers. The ability of the ternary alloying elements to enhance σICS, the elastic constants, and elastic modulus were in the order: Re > W > Mo > Ta. Our calculated elastic properties were consistent with reported experimental results for commercial superalloys (e.g., CMSX-4 and TMS-26), as well as with other reported computational results. Furthermore, the charge density difference of the γ/γ′ ternary alloys during compressive deformation were analyzed to understand the strengthening mechanisms of the alloying elements. The mechanical properties of the γ/γ′ ternary model alloys were predicted by modifying the first-order rule of mixtures (ROM) with the alloying element concentrations, and the determined values were in close agreement with the results of the first-principles calculations. •The compressive behavior of γ/γ′ ternary alloys were studied by ab initio calculations.•The ability of the alloying elements to enhance mechanic properties were in the order: Re > W > Mo > Ta.•Combining the Hill rule of mixtures (ROM) and concentrations, a modified ROM was derived for γ [001]/γ′ [001] multilayers.