TEM and 3D atom probe characterization of DMS4 cast nickel-base superalloy

Microstructure and creep behavior of DMS4-type nickel based superalloy single crystals with orientations near 〈001〉 and 〈011〉

“…The density and total refractory alloying element content of this alloy have been reported as 9.08 g/cc and 21.7 wt.%, respectively [20]. It may be noted that the average composition of this alloy differs significantly from that of other Re-containing superalloys such as CMSX-4, CMSX-10, Rene N5 and Rene N6 [21] due to its significantly higher Re and Ta content, and absence of Mo and Ti as alloying elements.…”

“…7 shows the presence of nanometer-scale spherical precipitates, which are believed to have been formed inside the channels in course of second and third aging treatments. Earlier studies [16,20] using three dimensional atom probe has shown the -interface as sharp with partitioning of Re to the -matrix and of Ta to the -precipitate. Table 3.…”

“…Furthermore, Ta addition has also been reported [19] to reduce the -lattice mismatch, increase the solvus temperature, and minimize the lowering of liquidus and solidus temperatures. The compositions of and phases in this alloy, as measured by three dimensional atom probe studies, have been reported elsewhere [20], with the lattice constant of being ≈0.362 nm.…”

“…Additions of Mo and Ti have been avoided in this alloy to ensure the stability of -phase [20]. Results of an earlier study have shown that absence of Mo can inhibit the formation of Ni-Cr-Mo based topologically close-packed (TCP) phases [23] on exposure at high temperatures (>900 • C) during a creep test for an extended period.…”

Effect of Off‐Stoichiometry and Ternary Additions on Planar Fault Energies in Ni 3 Al

“…The third set of calculations closely mimics γ΄ composition in commercial superalloys [6,7]. Simultaneous presence of both Ti and Ta was not explored.…”