Investigation of the elemental partitioning behaviour and site preference in ternary model nickel-based superalloys by atom probe tomography and first-principles calculations

The Importance of Diffusivity and Partitioning Behavior of Solid Solution Strengthening Elements for the High Temperature Creep Strength of Ni-Base Superalloys

“…In contrast, Ru segregates preferentially in the c-phase (k i c¢/c = 0.53). This is in agreement with APT investigations of Liu et al and Ding et al as well as TEM-EDS measurements of Pyczak et al [37][38][39] The partitioning behavior of Mo in the three Mo-containing alloys, Astra2-Mo, Astra2-MoW and Astra2-ReMo, is similar. The lowest partitioning coefficient of 0.39 was observed for Mo in Astra2-MoW.…”

“…Many microstructural factors, such as the c¢-volume fraction, c¢-size and c-channel width, contribute to the creep strength of Ni-base superalloys at elevated temperatures. [13,29,37,38,41] The adjusted heat treatments lead to similar c¢-size and also the c¢-volume fractions differ only slightly between most of the investigated Astra2 alloys. Their minimum creep rate _ e min is plotted as a function of the c¢-volume fraction after the full heat treatment at 1143 K (870°C) for 24 hours and after the long-term heat treatment at 1373 K (1100°C) for 1000 hours in Figure 8.…”

The Effects of Chemistry Variations in New Nickel-Based Superalloys for Industrial Gas Turbine Applications

“…From an alloy design perspective, it is important to assess what gives rise to interfacial solute segregation and, more so, how this might impact high-temperature creep resistance. Early APT studies hypothesized that Blavette and Bostel [82] CMSX-2 a a a b b bà b Blavette et al [83] ONERA alloy a a a b b bà Nb: b Miller and Horton [71] Ni-Al-B-X (X=Co/Hf/Fe) a a b b b à Blavette et al [84] CMSX-2 and PWA1480 a a a b b b b Re: b More and Miller [85] Udimet 720 a a a b b b b Harada et al [86] TMS-63 a a b b b Duval et al [87] MC2 a bà ¼ b b b b b Miller et al [88] PWA1480 a aà a b b b b Murakami et al [89] CMSX-4 Re: b Jayaram and Miller [90] Ni-Al-Ta-Mo a ¼ b b Wanderka and Glatzel [75] CMSX-4 a a a ¼ b a b Murakami et al [91] TMS-79 a a b b b Ir: b Cadel et al [92] N18 a b a b b b Booth-Morrison et al [43] Ni-Al-Cr-Ta a bà b b Zhou et al [93] Ni-Al-Cr-X (X=Re/Ru) a b b Re, Ru: b Tu et al [94] Ni-Al-Mo a b b Tiley et al [95] Rene´88 a b ¼ b b Liu et al [96] Ni-Al-X (X=Cr/Co/Ru) a b ¼ b Ru: b Oni et al [97] Ni-Al-Co-Ti a ¼ b b Bagot et al [38] RR1000 a a a bà b b b b…”

First-principles study of solute diffusion in Ni 3 Al

“…According to our previous work about the site preference of ternary alloying additions, most metal elements exhibit a strong Al site preference in the dilute ternary ordered L1 2 structure. [50] For the one-step NN jump, the solutes that preferentially occupy Al sites jump from the Al to the Ni sublattice, resulting in an inter-sublattice jump. From Fig.…”

“…The above results agree with our previous reports about the site preference of transition metal elements in L1 2 Ni 3 Al. [50] The schematics of the possible jump pathways and MEP plots for AS and ASB mechanisms for solutes diffusion in Ni 3 Al are shown in Fig. 3, and the energy barriers for candidate mechanisms are listed in Table 5.…”