Virtual MSE Colloquium: Rishi Pillai, Designing corrosion resistant high temperature alloys: possibilities and outlook

All dates for this event occur in the past.

Virtual only
United States

Rishi Pillai

High Temperature Corrosion Science and Technology
Materials Science and Technology Division
Physical Sciences Directorate
ORNL

Abstract

High-temperature material solutions for the future need to withstand higher than usual operating temperatures and harsher environments due to the drive to improve the durability and efficiency of components in power generation and transport industries. Sequential materials design approaches strive to achieve individual physical properties but fail to anticipate the consequences of complex interactions between underlying phenomena, such as environmental degradation and thermomechanical stability, that can substantially impact efficiency, performance, and lifecycle requirements. Coupled extremes of high temperatures and corrosive environments drive compositional changes in the materials that further lead to the detrimental subsurface dissolution of strengthening phases or formation of deleterious precipitates. A paradigm shift in the traditional sequential design approaches is critically essential to create application-specific hierarchical and multifunctional materials with superior long-term performance for next-generation energy technologies involving extreme environments. From a development standpoint, the lifetimes are too long for experimental verification, and meeting the requirements of expected lifetimes at a reasonable cost is only possible through accurate and validated computational methodologies.

A previously developed coupled thermodynamic-kinetic modeling approach has been successfully employed to describe the microstructural evolution in some of the widely used types of uncoated and coated high-temperature alloys as a function of alloy/coating composition, environment (air, steam, supercritical CO2, molten salts), time and temperature. Such a tool will enable effective codesign of novel materials systems that balance multiple and competing objectives and trade-offs between various demands within a system’s lifetime performance. The practical applicability of the model ranges from heat exchangers, industrial furnaces, molten salt reactors, gas turbines, jet engines to other power generation components (boilers, tubing, containment structures). The microstructural development in the relevant alloys was modeled by considering simultaneously occurring oxidation/corrosion, diffusion, and dissolution/precipitation processes. The modeling results were validated with long-term experimental data combined with a detailed microstructural characterization using multiple techniques. Element concentrations and phase distribution were obtained by scanning electron microscopy (SEM). Phases were identified by energy/wavelength dispersive X-ray spectroscopy (EDX/WDX) and electron backscatter diffraction (EBSD). The talk will provide a brief overview of high-temperature corrosion, focus on the applicability of existing computational approaches to design corrosion-resistant alloys, and provide a brief outlook on the future of computation-assisted materials development.

Rishi Pillai
Rishi Pillai
Research Staff - ORNL

Bio 

Rishi Pillai is Research Staff in the Corrosion Science and Technology group at ORNL since 2018. He received his Ph.D. in Materials Science from the Aachen Technical University (RWTH), Aachen, Germany in 2014. His previous experience includes working as a Research Associate in the High-Temperature Corrosion and Corrosion Protection group at the Julich Research Center (Forschungszentrum Julich), Germany between 2013-2018. His main research areas are the experimental and computational evaluation of the high-temperature behavior of ferritic and austenitic steels, Ni-base alloys, and high-temperature corrosion/oxidation resistant coatings. The computational work includes the development of modeling methodologies to allow a physics-based prediction of corrosion-induced degradation and residual lifetime assessment.

 


Dr. Pillai will be presenting virtually. 

Zoom Link
Meeting ID: 994 4212 1610
Password: 351334