The research objective of this collaborative study is to demonstrate a comprehensive understanding of modeling and control of Friction Surfacing-based Additive Manufacturing by creating a functionally graded, multi-layered weld transition joint between chrome moly steel (T91) and austenitic stainless steel (AISI316). The research approach will be to apply various nickel based alloy layers by friction surfacing, creating a smooth and gradual transition in physical and metallurgical properties to improve their creep life. The experimental program involves stress rupture and creep-fatigue tests to assess the creep behavior of the transition joints. The research approach for in-situ finite element modeling involves development of fine-scale crystal plasticity and homogenized anisotropic continuum plasticity models, which will help in obtaining the optimized process parameters for the fabrication of components using Friction Surfacing-based Additive Manufacturing.
If successful, this research will aid the accelerated deployment of T91 and AISI316 weld transitional joints for structures in emerging initiatives including boiler, nuclear and clean energy concepts. Through the finite element model development, not only can T91/316 joints be made, but a basic modeling and manufacturing infrastructure will be developed that can be applied to any application where transitional joints are needed between hard-to-process materials and/or materials where fusion welding produces undesirable intermetallic formation. The successful completion of this research will enable higher-temperature power plants to generate power 1) at lower cost 2) with lower greenhouse gas emissions and 3) in larger quantities resulting in a better quality of life. The results will also help make it possible to manufacture better performing and optimized components in a host of other engineering industries. The educational objectives of the proposal will focus on training of post-doctoral researchers, graduate and undergraduate students. Advanced Surface Technology course will be developed which will expose the students to the state-of-the-art advances in manufacturing technologies.
