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A Computational Approach to Homogenizing Nick-Based Single Crystal Alloys

National Energy Technology Laboratory

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Technology Marketing Summary

An innovative approach has been developed to improve the thermal processing of advanced Nickel (Ni) single crystal alloys. The method employs thermodynamic and kinetic modeling to efficiently predict and optimize superalloy homogenization resulting in materials with superior properties. Significantly, the subject approach allows the homogenization process to be tailored for the desired end-use of the superalloy, while minimizing effort and cost. This technology is available for licensing and/or further collaborative research with the U.S. Department of Energy’s National Energy Technology Laboratory.

Description

Ni-based superalloys are a unique class of metallic materials possessing an exceptional combination of high temperature strength, durability and resistance to degradation in corrosive or oxidizing environments. Such characteristics make Ni-based superalloys ideal for application in harsh environments such as aircraft and power-generation turbines, rocket engines and chemical processing plants. Optimal superalloy performance requires thermal processing subsequent to manufacture and prior to use. This processing typically involves homogenization heat treatment to evenly distribute the alloying elements throughout the superalloy microstructure, minimizing the adverse, performance-reducing effects of solute non-uniformity. Next to superalloy composition, the homogenization is the primary method of tailoring a superalloy for optimal performance in its intended use. 

Traditionally, the homogenization process has been performed in a time-consuming, costly, empirical manner. This is a particularly daunting task given that typical Ni-based superalloys contain 10 to 15 alloying elements and uniform chemistry is highly critical to performance. In light of this, researchers at NETL have developed a computationally-based approach to homogenization heat treatment of Ni-based superalloys that delivers consistent levels of homogenization in a time and cost-effective manner.

Briefly, the Scheil module of Thermo-Calc software is employed to predict the as-cast, superalloy-specific microstructure (i.e., unique microsegregation of the alloying components) present within the superalloy. The subsequent segregation profiles are read into DICTRA, a software package for simulating diffusion in multicomponent alloys, to refine the homogenization treatment. This allows for a simulated heat treatment of the superalloy casting. Significantly, the ‘computational homogenization’ incorporates the resulting heat-induced redistribution of the alloying elements, successively raising the heat treatment temperatures until the desired level of homogenization is achieved. The result is the identification of a homogenization strategy that provides optimal results in hours, not days, as with conventional empirical methods.

Benefits
  • Provides significantly diminished processing costs, including reduced energy consumption and throughput times, and increased availability of capital equipment such as furnaces, due to shorter heat treatments
  • Generates superior Ni-based superalloys with improved performance in downstream applications
  • Provides extreme flexibility, allowing for modification to meet the differing constraints of individual production facilities and the level of homogenization desired
Applications and Industries
  • Any Ni-based superalloy used in severe environments such as aerospace engines, oxy-fuel combustion boilers and steam turbines (e.g., advanced ultra supercritical conditions), chemical processing facilities and fossil energy recovery (e.g., high pressure/high temperature drilling)
More Information

U.S. Non-Provisional Patent Application No 13/528,958; titled "Method of Determining a Stepped Approach to a Maximum Temperature in the Homogenization of a Metal Alloy."

Inventors: Paul Jablonski, Christopher Cowen.

U.S. Provisional Patent Application, No. 62/039,450, titled "A Computational Approach to Homogenizing Alloys" filed on August 20th, 2014.

Inventors: Paul D. Jablonski, Jeffrey Hawk

Technology Status
Development StageAvailabilityPublishedLast Updated
PrototypeAvailable05/18/201705/18/2017

Contact NETL About This Technology

To: Jessica Sosenko<jessica.sosenko@netl.doe.gov>