The influence of coherency strain on the elevated temperature tensile behavior of Ni-15Cr-AI-Ti-Mo alloys

The microstructure and hardness of Ni-Co-Al-Ti-Cr quinary alloys

“…However, three compositions were found to only loosely depend on the lattice misfit, and displayed hardness values of ~ 250 Hv. Whilst these results appear to be consistent with the findings of Grose and Ansell [77] who suggested that low lattice misfit alloys are less dominated by coherency strengthening, removing these three data points did not produce a considerable change in the variation of alloy hardness with lattice misfit (0.1% change in the misfit was translated to a ~ 60Hv change in the hardness). This suggests that Co-based alloys may indeed be more strongly dependent upon lattice misfit than their Ni-based or NiCo-based counterparts.…”

“…Several studies have sought to quantify the effect of lattice misfit and coherency strengthening on the mechanical properties of superalloys [72,[75][76][77][78][79]. Gerold and Haberkorn [75] used rigorous mathematical analyses combining linear elasticity theory with statistical approximations to formulate the interactions of the precipitate stress field with a dislocation, assuming a spherical stress field, a straight dislocation line and an elastically isotropic matrix.…”

“…Ardell [78] in his 1985 review of precipitation hardening, offered a thorough explanation of the limitations of the theoretical mathematical approaches used to that date, and suggested that these arise primarily from the statistical averaging operations required and due to the assumptions associated with the deformation mechanism. In contrast to the theoretical approaches used by most researchers, Grose and Ansell [77], followed an empirical, experimental approach, in which a set of alloy compositions were designed in order to isolate and examine various aspects of strengthening behaviour. The results obtained indicated that for alloys in which the lattice misfit was high, the flow stress (normalised against volume fraction) displayed a very strong near-linear dependence on the lattice misfit.…”

Effect of Nb and Ti Addition on Microstructure and Hardness of Dual Two-Phase Intermetallic Alloys Based on Ni<SUB>3</SUB>Al-Ni<SUB>3</SUB>V Pseudo-Binary Alloy System

“…The morphologies and roles of these interfacial dislocations have been extensively studied by many researchers. [25][26][27][28][29][30][31][32][33][34][35] For an example, it was reported that as the density (or spacing) of the intrinsic interfacial dislocations increases the creep strength increases. 34) In the dual two-phase intermetallic microstructures, there are several kinds of interfaces: primary Ni 3 Al precipitate/eutectoid region, which is sub divided to (1) primary Ni 3 Al precipitate/decomposed Ni 3 Al in eutectoid region and (2) primary Ni 3 Al precipitate/decomposed Ni 3 V in eutectoid region, and interfaces in eutectoid region, which are sub divided to (3) decomposed Ni 3 Al/decomposed Ni 3 V and (4) variant interfaces between Ni 3 V phases composed of the lamellar structures.…”

Cooling Rate Dependent Morphology of the γ' Precipitates in Nickel-Base Superalloy Udimet 500

“…precipitates from the bulk sample, respectively, and γ a is the lattice constant of the matrix phase [7]. In addition, the difference between the lattice constant for the constrained, b a γ ′ , and unconstrained γ΄ leads to an elastic strain, ε e , in constrained γ΄ which is calculated by Eq.…”