Influence of Chemistry on the Tensile Yield Strength of Nickel-Based Single Crystal Superalloys

Abstract

Abstract. The tensile yield strength of AM1 and MC-NG single crystal superalloys with a γ' precipitate size close to 300 nm were compared within the 20-1050°C temperature range. The room temperature yield strength of the fourth generation MC-NG superalloy is about 200 MPa less than that of the AM1 first generation one. Inversely, at higher temperatures (T > 800°C), the tensile strength of MC-NG is higher than that of AM1. These results are discussed by taking into account the elementary deformation mechanisms and the respective strengths of the γ and γ' phases. Experiments on a modified MC-NG alloy show that reinforcing the γ' phase by increasing the contents of Ti and Ta is an efficient way to recover a higher tensile strength at low temperatures. Rhenium addition and increase of the γ' solvus temperature are suggested to be beneficial for the high temperature tensile strength. Data published on various other single crystals are in agreement with these hypotheses.

Influence of Residual Stresses on the Fatigue Life of a Shot‐Peened Nickel‐Based Single Crystal Superalloy: From Measurements to Modeling

“…like the measured one in the reference sample. In Figure 4, the dashed lines represent the ultimate stress limit of the AMl material [15]. In Figure 4a stresses close to the sample surface are larger than this value.…”

“…Although each measurement is performed on a free surface, in the layer affected by the shot-peening process, T 33 significantly differs from zero when the metric tensor of the reference sample is used (Figure 4a). This is probably due to the modification of the material properties (solid solution gradients, loss of coherency strains) in this layer because of the strong hardening caused by shot-peening and the lattice parameter of the reference state should not be taken Dashed line corresponds to the ultimate stress of the AMl superalloy determined from tensile or fatigue tests at room temperature [15]. like the measured one in the reference sample.…”

Residual stress determination in a shot-peened nickel-based single-crystal superalloy using X-ray diffraction

“…In the AM1 superalloy, the ultimate stress determined from tensile or fatigue tests at room temperature is close to 1100 MPa for samples that have not been subjected to shot-peening (Caron et al, 2011). This contradiction may be removed if we consider that in the surface layer the original material is hardened and that macroscopic stresses measured by a load cell in mechanical tests may differ significantly from internal stresses which develop locally at the microscopic scale.…”

A new single crystal high entropy alloy with excellent high-temperature tensile property

“…To some extent, the more difficultly the dislocation moves, the higher strength the alloy possesses. In the γ′ precipitation-strengthening alloys, the dislocations originate the γ matrix channel, moves to the interface, and finally go into the γ′ particles [38]. The element addition could have effects on the dislocation movements in both γ and γ′ phases [38].…”

“…In the γ′ precipitation-strengthening alloys, the dislocations originate the γ matrix channel, moves to the interface, and finally go into the γ′ particles [38]. The element addition could have effects on the dislocation movements in both γ and γ′ phases [38]. Firstly, the effect of solid-solution strengthening elements on the dislocation is discussed.…”