WE Colloquium: Michael Kirka, Processing of Traditionally non-weldable Ni-base Superalloys by Additive Manufacturing

Abstract

Nickel-base (Ni-base) superalloys can be considered a pinnacle of materials science and mechanical engineering due to the capabilities of the alloy family: Withstand highly corrosive environments, creep-fatigue conditions, all the while operating and maintaining integrity at temperatures greater than two-thirds their melt point. Through their history, the performance of gas turbine engines has been linked to the combined developments in superalloy metallurgy, coating technology, and component design. However, over time each linkage has plateaued in contribution to overall engine performance due to technological limitations. With the advancement of additive manufacturing technologies, the promise of component design flexibility and enhancement is presented. To be discussed is ongoing work focusing on addressing the challenges of implementing additive techniques for this purpose. To take advantage of the promise additive manufacturing offers and apply it to gas turbine engines, knowledge of how to overcome the processing challenges of the highly non-weldable Ni-base superalloys is required. For this process understanding and thermal management is required. Beyond processing, computational approaches for optimizing mechanical performance and predicting performance of the AM material under service-like conditions is required for determining alloy suitability for in-depth evaluation and deployment. As such, coupled experimental and computational approaches have been demonstrated for Ni-base superalloys manufactured by traditional means which can be readily applied for the deployment and evaluation of AM processed Ni-base superalloys.

Bio

Dr. Michael Kirka is a Materials Scientist within the Deposition Science and Technology Group at Oak Ridge National Laboratory. Michael’s current research focuses on evaluating the suitability and limitations of high temperature Nickel-base (Ni-base) superalloys for additive manufacturing processes through understanding their microstructural evolution during processing in relation to their microstructure-property relationships. Additionally, Michael work on developing heat-treatments specific to Ni-base superalloy processed via additive manufacturing. Previously, Michael’s research has focused on laser based repair techniques for Ni-base superalloy gas turbine airfoils and understanding the thermomechanical material degradation mechanisms in nickel-base superalloys exposed to service like conditions. Michael received his B.S. in materials science 2007 from The University of Michigan and M.S. and Ph.D. degrees from The Georgia Institute of Technology in mechanical engineering in 2010 and 2014 respectively.