Homogenizing a Nickel-Based Superalloy: Thermodynamic and Kinetic Simulation and Experimental Results

Jablonski, Paul D.; Cowen, Christopher J.

doi:10.1007/s11663-009-9227-1

Cited by 68 publications

(31 citation statements)

References 5 publications

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“…The balance of the alloy constituents were set to the nominal Haynes 282 chemistry. The gamma prime misfit of each alloy was determined computationally using JMatPro software [5]. Each heat was melted in a vacuum induction furnace and cast with 50°C superheat above the Thermo-Calc predicted liquidus for each formulation.…”

Section: Methodsmentioning

confidence: 99%

Effects of Al and Ti on Haynes 282 with Fixed Gamma Prime Content

Jablonski¹,

Cowen²,

Hawk³

2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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ABSRACTTraditionally, high temperature components within coal fired power plants are manufactured from ferritic/martensitic steels. However, the proposed steam temperature in the Advanced Ultra Supercritical (A-USC) power plant is high enough (760°C) that ferritic/martensitic steels will not work due to temperature limitations of this class of materials; thus Ni-based superalloys are being considered. The life cycle requirements of such alloys are very demanding and are on the order of several hundred thousand hours. In this paper a wrought Ni-based superalloy with a fixed amount of gamma prime strengthening phase will be examined, with either low Al or low Ti contents, but still within the alloy 282 nominal chemistry specification. The effect that these changes have on the gamma prime misfit and its relevance to long-term microstructural and creep strength stability will be explored both experimentally as well as with computational thermodynamics.

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Section: Methodsmentioning

confidence: 99%

Effects of Al and Ti on Haynes 282 with Fixed Gamma Prime Content

Jablonski¹,

Cowen²,

Hawk³

2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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“…After casting and sampling for chemistry, each was subjected to a computationally optimized homogenization heat treatment [6][7]. This was important because the castings were found to be inhomogeneous due to nonequilibrium solidification resulting in localized regions poor in Cr and Al (potentially impacting oxidation resistance) as well as Al, Ti and Mo (potentially impacting strength).…”

Section: Methodsmentioning

confidence: 99%

“…Post homogenization the castings were given their recommended aging heat treatment. The effectiveness of the homogenization cycle was evident in the microstructure [6] as well as in the creep performance [8] which was found to be comparable to the wrought versions of the alloys.…”

Section: Methodsmentioning

confidence: 99%

“…For all three alloys, it was found that the cast versions performed comparably to their wrought counterparts. This is due in part to the homogenization heat treatment [6][7] given each alloy prior to peak aging. Without this heat treatment, critical strengthening elements such as Al, Ti, and Mo would be concentrated either in the dendrite cores or interdendritic regions of the cast material.…”

Section: Cast and Homogenized Wroughtmentioning

confidence: 99%

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Cast Alloys for Advanced Ultra Supercritical Steam Turbines

Holcomb¹,

Jablonski²,

Wang³

2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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The proposed steam inlet temperature in the Advanced Ultra Supercritical (A-USC) steam turbine is high enough (760 °C) that traditional turbine casing and valve body materials such as ferritic/martensitic steels will not suffice due to temperature limitations of this class of materials. Cast versions of three traditionally wrought Ni-based superalloys (Haynes 263, Haynes 282, and Nimonic 105) were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantial: 2-5,000 kg each half and on the order of 100 mm thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equivalent microstructures. A multi-step homogenization heat treatment was developed to better disperse the alloy constituents. These castings were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (at 760 and 800 °C).

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“…The models for additional strengthening mechanisms, such as solid solution strengthening and Hall-Petch effect, have also been implemented based on the statistical analyses [49,73]. Using these strengthening models, the processing conditions (processing temperature and time) are chosen to maximize the yield strength of the microstructure [3,41,91].…”

Section: Yield Stressmentioning

confidence: 99%

A Computational Framework for Material Design

Kattner

Campbell

2017

Integr Mater Manuf Innov

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A computational framework is proposed that enables the integration of experimental and computational data, a variety of user-selected models, and a computer algorithm to direct a design optimization. To demonstrate this framework, a sample design of a ternary Ni-Al-Cr alloy with a high work-to-necking ratio is presented. This design example illustrates how CALPHAD phase-based, composition and temperature-dependent phase equilibria calculations and precipitation models are coupled with models for elastic and plastic deformation to calculate the stress-strain curves. A genetic algorithm then directs the search within a specific set of composition and processing constraints for the ideal composition and processing profile to optimize the mechanical properties. The initial demonstration of the framework provides a potential solution to initiate the material design process in a large space of composition and processing conditions. This framework can also be used in similar material systems or adapted for other material classes.Keywords Ni-based superalloy · Integrated computational materials engineering · Genetic algorithm · Material design

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Homogenizing a Nickel-Based Superalloy: Thermodynamic and Kinetic Simulation and Experimental Results

Cited by 68 publications

References 5 publications

Effects of Al and Ti on Haynes 282 with Fixed Gamma Prime Content

Effects of Al and Ti on Haynes 282 with Fixed Gamma Prime Content

Cast Alloys for Advanced Ultra Supercritical Steam Turbines

A Computational Framework for Material Design

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