Enabling Multi-scale Modeling by Deciphering Fundamental Mechanisms Underlying Phase Stability, Deformation and Oxidation in Refractory Complex Concentrated Alloys (RCCAs) and Intermetallics
Abstract
There has been an ever-increasing demand for new high temperature alloys, especially those capable of extending the temperature domain of turbine engine hot section materials to beyond 1000°C. At present, increases in turbine engine efficiency are hindered by material-property limitations of currently employed cast single crystal (directionally solidified) Ni-base superalloys. Therefore, there is a need for a new class of high temperature alloys to be developed. High entropy alloys (HEAs) or complex concentrated alloys (CCAs) have emerged as an exciting new class of structural materials that transform the traditional alloy design from a single principal element paradigm to one consisting of multiple equimolar elements forming a single-phase solid-solution. CCAs, in contrast to the earlier approaches of adding elements to a ‘parent’ matrix, enable us to create novel alloys with targeted properties by focusing on the unexplored central region of a multicomponent phase diagram. However, the focus on a single-phase microstructure seriously limits performance at elevated temperatures. The proposed program will significantly extend the HEA paradigm to multi-phase complex-concentrated alloys (CCAs), focusing on those containing a substantial fraction of refractory elements, also referred to as RCCAs, for demanding engineering applications with a focus on high temperature aircraft structural applications. These alloys will retain the “high entropy” nature of the parent matrix and add complex ordered precipitate strengtheners, often containing multiple elements on their respective sub-lattices. This will require developing new science to describe the behavior of these complex systems and to integrate this new science with advanced computational and characterization tools to create unprecedented predictive schemes that permit full exploitation of these unexplored systems. Therefore, multiphase RCCAs hold potential promise as the next generation of high temperature alloys.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 21, 2022
- Source ID
- FA95502110304XX0
Entities
People
- Rajarshi Banerjee
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of North Texas