Ageing kinetics of Ni-base superalloys

Gorgannejad, Sanam; Rodas, Ernesto A. Estrada; Neu, Richard W.

doi:10.1080/09603409.2016.1176753

Cited by 13 publications

(14 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Re is added to second‐generation single‐crystal superalloys to optimize their creep‐rupture response . Re had been shown to retard the rate of coarsening of the γ′ phase because, for the precipitates to coarsen, Re that segregates almost exclusively to the γ channels needs to diffuse away from the γ/γ′ interface . Since Re is a larger atom compared with Ni, its diffusion is small .…”

Section: Materials Descriptionmentioning

confidence: 99%

“…Interesting, when the oxidation‐assisted fatigue mechanism is operating under zero‐compression loadings, the differences in lives between lower Re and 3% Re superalloys are much less than a factor of two, suggesting that the main benefit of the Re is reducing creep and stabilizing the precipitates. The coarsening and rafting of the γ′ precipitates is faster when there is less Re, which can be predicted by CALPHAD models that account for the increase in diffusivity when Re is reduced …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Creep‐fatigue behaviour of single‐crystal Ni‐base superalloy CMSX‐8

Rodas

Gorgannejad

Neu

2019

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

The creep‐fatigue behaviour of a lower cost, reduced rhenium Ni‐base superalloy, CMSX‐8, a variant of CMSX‐4, cast in a single crystal was experimentally evaluated over a broad range of conditions, from room temperature to 1100°C, and for two loading orientations: <001> and <111>. The fatigue lives depend on the orientation, cycle type, and temperature. The relative importance of these parameters on influencing the life is identified and discussed. From this understanding, a simple life model is constructed to capture the influence of these broad test conditions. The results are compared with those of the higher Re superalloy, CMSX‐4.

show abstract

Section: Materials Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Creep‐fatigue behaviour of single‐crystal Ni‐base superalloy CMSX‐8

Rodas

Gorgannejad

Neu

2019

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

show abstract

“…In particular, the pre‐aging was performed at 1100°C and uniaxial stress of 130 MPa for 50–60 h to evolve the microstructure to the fully‐rafted state depicted in Figure 4A, corresponding the N‐rafts since this is a negative misfit alloy, while the total creep deformation did not exceed 2%. This aging condition was determined from a prior study on the kinetics of microstructure evolution of CMSX‐8 16 to assure maximal morphology change and minimal deformation. For pre‐creep, the objective was to keep the γ / γ ′ microstructure nearly unchanged while introducing considerable creep strain associated with increase in the number of dislocations mainly in the γ channels.…”

Section: Test Plan and Methodsmentioning

confidence: 99%

“…[3][4][5][6][7] For common blade alloys, the volume fraction of the γ 0 precipitates is quite high, ranging from 0.6 to 0.75. Since the γ/γ 0 structure readily evolves at higher temperatures with the evolution dependent on the stress level coupled with a limited amount of inelastic deformation, [8][9][10][11][12][13][14][15][16][17] the creep behavior of single-crystal superalloys can be put in one of three categories tied to the morphology and state of the γ/γ 0 structure which can be generally grouped by stress level and temperature, as illustrated in Figure 1. Microstructure evolution leading to rafting (directional coarsening) occurs at high temperatures and low stress influenced by misfit stresses at the γ/γ 0 interphase.…”

Section: Introductionmentioning

confidence: 99%

Employing sequential experiments to gain insights on the interaction between creep and fatigue damage in Ni‐base superalloys

Gorgannejad

Rodas

Neu

2022

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

The interaction between creep and fatigue damage in Ni-base superalloy CMSX-8 was explored using a sequential workflow that decouples creep and fatigue steps to quantify how accumulated creep damage interacts with subsequent isothermal low-cycle fatigue (LCF) and vice versa. Two workflows were considered: creep followed by LCF and LCF followed by creep. For the first workflow, the subsequent LCF was evaluated at temperatures of 20 C, 750 C, and 1100 C. It was found that the extent of deleterious interaction of prior creep on LCF depended on increasing subsequent fatigue test temperature. For the LCF followed by creep, fatigue tests were first conducted at 20 C and 1100 C to 60% of life, and then creep was conducted at 800 C, where primary creep is promoted, or 900 C, where primary creep is absent. LCF damage accumulated at 1100 C accelerated creep and decreased ductility, while fatigue damage at room temperature had minimal effect on the creep behavior.

show abstract

“…us, the microstructural stability, which is related to the mechanical integrity of this component, acquires major technological and scientific interest. So, several experimental and theoretical efforts have been made to predict or estimate the phase evolution of superalloys under different aging conditions [7,[10][11][12]. Other phases like the topologically packed phases (TCP) can frequently appear into the microstructure of Ni-based superalloys.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analyses of the Effect of Heat Treatments on the Phase Stability of Inconel 792

Cueto-Rodriguez

Ávila-Dávila

López-Hirata

et al. 2018

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

A study about the precipitation and phase stability was carried out in an IN-792 superalloy used as a blade in a gas turbine. Microstructure analysis was conducted experimentally on three different cross sections of the blade designated as high temperature (HT), medium temperature (MT), and low temperature (LT). To identify the HT, MT, and LT sections, a numerical thermal analysis was performed using ANSYS software. To obtain the distribution gradient of temperature in the blade, the real conditions of operation in steady state of the gas turbine were considered. A numerical study about the occurrence of phases in the IN-792 superalloy was carried out with ermo-Calc and TC-PRISMA software. e analysis of the as-cast IN-792 superalloy with Scheil-Gulliver equations permitted to explain the phase formation during the solidification process. e calculated timetemperature-precipitation (TTP) diagram explains consistently the precipitation process observed after two different heat treatment conditions applied experimentally and numerically to regenerate the original microstructure of the IN-792 superalloy. e experimental results were consistent with the calculated isoplethic and TTP diagrams. In terms of accuracy, the further development of the ermo-Calc databases for thermodynamic calculations in superalloys is evident. It was possible to calculate precipitation temperatures and the local evolution of precipitated particles for two different heat treatment conditions.

show abstract

Ageing kinetics of Ni-base superalloys

Cited by 13 publications

References 34 publications

Creep‐fatigue behaviour of single‐crystal Ni‐base superalloy CMSX‐8

Creep‐fatigue behaviour of single‐crystal Ni‐base superalloy CMSX‐8

Employing sequential experiments to gain insights on the interaction between creep and fatigue damage in Ni‐base superalloys

Numerical and Experimental Analyses of the Effect of Heat Treatments on the Phase Stability of Inconel 792

Contact Info

Product

Resources

About