Constitutive Equations for the Thermomechanical Response of Rene´ 80: Part 1—Development From Isothermal Data

This work describes the development of a unified nonisothermal constitutive model to predict the thermomechanical fatigue (TMF) response of a Nickel base superalloy, Rene´ 80. Nonisothermal deformation mechanisms are modeled using state variables. The flow equation of the Ramaswamy-Stouffer model was rewritten in the form of an Arrhenius equation with explicit temperature dependence. The isothermal predictions were correlated with the test data at four test temperatures between 538°C and 982°C. Material parameters were verified using nonisothermal tensile calculations. This verification showed that modeling the transition between planar slip and dislocation climb accurately is crucial for obtaining reliable TMF predictions. The revised constitutive model could successfully predict Rene´ 80 response from several TMF tests between 760°C and 982°C.

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Effect of long-term aging on the microstructure, stress rupture properties and deformation mechanisms of a new cast nickel base superalloy

Materials Science and Engineering A ◽

10.1016/j.msea.2018.08.096 ◽

2018 ◽

Vol 736 ◽

pp. 76-86 ◽

Cited By ~ 12

Author(s):

Meiqiong Ou ◽

Yingche Ma ◽

Hualong Ge ◽

Bo Chen ◽

Shijian Zheng ◽

...

Keyword(s):

Stress Rupture ◽

Deformation Mechanisms ◽

Nickel Base Superalloy ◽

Stress Rupture Properties ◽

Nickel Base ◽

Rupture Properties ◽

Base Superalloy

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High-temperature deformation mechanisms in a polycrystalline nickel-base superalloy studied by neutron diffraction and electron microscopy

Acta Materialia ◽

10.1016/j.actamat.2014.04.028 ◽

2014 ◽

Vol 74 ◽

pp. 18-29 ◽

Cited By ~ 49

Author(s):

E.M. Francis ◽

B.M.B. Grant ◽

J. Quinta da Fonseca ◽

P.J. Phillips ◽

M.J. Mills ◽

...

Keyword(s):

Electron Microscopy ◽

High Temperature ◽

Neutron Diffraction ◽

Deformation Mechanisms ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Nickel Base Superalloy ◽

Polycrystalline Nickel ◽

Nickel Base ◽

Base Superalloy

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Efficient Methodologies for Determining Temperature-Dependent Parameters of a Ni-Base Superalloy Crystal Viscoplasticity Model for Cyclic Loadings

Journal of Engineering Materials and Technology ◽

10.1115/1.4027857 ◽

2014 ◽

Vol 136 (4) ◽

Cited By ~ 2

Author(s):

M. M. Kirka ◽

D. J. Smith ◽

R. W. Neu

Keyword(s):

Fatigue Behavior ◽

Deformation Mechanisms ◽

Turbine Engines ◽

Nickel Base Superalloy ◽

Gas Turbine Engines ◽

Directionally Solidified ◽

Temperature Dependent ◽

Nickel Base ◽

Calibration Time ◽

Base Superalloy

The prediction of temperature-dependent fatigue deformation and damage in directionally solidified and single-crystal nickel-base superalloy components used in the hot section of gas turbine engines requires a constitutive model that accounts for the crystal orientation in addition to the changing deformation mechanisms and rate dependencies from room temperature to extremes of the use temperature (e.g., 1050 °C). Crystal viscoplasticity (CVP) models are ideal for accounting for all of these dependencies. However, as the models become more physically realistic in capturing the true cyclic deformation mechanisms, increases the requirements to achieve an accurate model calibration. As a result, CVP models have yet to become viable for life analysis in industry. To make CVP models an industry relevant tool, the calibration times must be reduced. This paper explores methods to reduce the calibration time. First, a series of special calibration experiments are conceived and conducted on each relevant orientation and microstructure. Second, a set of parameterization protocols are used to minimize parameter interdependencies that reduce the amount of iteration required during the calibration. These experimental and calibration protocols are exercised using the CVP model of Shenoy et al. (2005, “Thermomechanical Fatigue Behavior of a Directionally Solidified Ni-Base Superalloy,” ASME J. Eng. Mater. Technol., 127(3), pp. 325–336) by calibrating a directionally solidified Ni-base superalloy across an industry relevant temperature range of 20 °C to 1050 °C.

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