Strengthening by γ/γ′ interfacial dislocation networks in TMS-162—Toward a fifth-generation single-crystal superalloy

Inhomogeneity of misfit stresses in nickel-base superalloys: Effect on propagation of matrix dislocation loops

“…The effects also should increase with temperature due to the increase of the absolute value of γ/γ'-misfit. 4. In single-crystal nickel-base superalloys of the newest generations with a high concentration of refractory elements the γ/γ'-misfit is very high.…”

“…During the primary stage of high temperature creep the coherency stresses between γ-and γ'-phase are relaxed by interfacial dislocation networks, a process which is designated as loss of coherency of the γ/γ'-interfaces. The formation mechanism of these networks was extensively studied by [1][2][3][4][5][6][7][8][9], with the unanimous conclusion, that during primary creep a/2〈110〉 dislocation loops are gliding on {111}-planes through matrix channels. At the intersection between {100}-interface and glide plane they leave behind 〈 1 1 0 〉 oriented dislocation segments.…”

Compositional effect on TCP phase formation in Ru-containing Ni-based single crystal superalloys

“…Although the excessive additons of Cr and Mo could induce a negative effect on microstructural stability, their additions benefit the improvement of creep properties [15,16]. Therefore, it is worthy to evaluate the effects of Cr and Mo additions and maximize their capacity to increase the creep resistance.…”

Effects of Ru additions on the microstructure and phase stability of Ni-base superalloy, UDIMET 720LI

“…[22] As previously discussed in Section IV, Ru preferentially partitions to the ␥ phase, and the Ru additions have no effect on the partitioning of other elements (Cr, Co, Mo, and Ni); thus, the Ru additions increase the lattice parameter of ␥ more than ␥Ј, [23] causing the lattice misfit to become more negative. Zhang et al [24] studied the effect of the lattice misfit induced by the Ru additions on microstructural stability; they found that the higher lattice misfit caused by the Ru additions results in a denser dislocation network, which can hinder the coarsening of the ␥Ј phase as well as provide a certain degree of strengthening. On the other hand, Reed et al [20] have quantified the interdiffusion rates of the 4d transition metals (from Nb to Ag) in Ni, by analyzing diffusion couples exposed to high temperatures; they found that Ru displays the slowest rate of interdiffusion in Ni in the 4d transition metals.…”