DMREF: Collaborative Research: GOALI: Localized Phase Transformation (LPT) Strengthening for Next-Generation Superalloys

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Extraordinary Properties This Designing Materials to Revolutionize and Engineer our Future (DMREF) Grant Opportunity for Academic Liaison with Industry (GOALI) award supports an integrated experimental and computational effort to accelerate the discovery of new typs of Ni-base superalloys that will have superior high-temperature creep performance, but most likely will have been missed by the traditional trial-and-error method. Ni-base superalloys are critical enabling high-temperature structural materials that determine the efficiency and carbon footprint of a wide range of aerospace and land-based power generation systems such as gas turbines. This effort is an integral part of the national efforts under the Materials Genome Initiative (MGI) and the Integrated Computational Materials Engineering (ICME) initiative. For the first time, superalloy development will be led by computational modeling, mechanistically informed and validated by critical experiments involving novel combinatorial methods for materials processing and state-of-the-art characterization techniques. Because future materials R&D activities, requiring substantially reduced time and cost cycles, must integrate computational materials research with critical experiments, this research project will directly prepare graduate students to immediately contribute to the success of MGI/ICME in industry. Additionally, the training programs for researchers involved in materials development will accelerate the implementation of the new methodology in industry, resulting in increased effectiveness of the US materials technologists. Regarding educational outreach, the present DMREF program will engage undergraduate researchers as mentors who develop K-12 engineering outreach activities encouraging high school students with diverse ethnic backgrounds to enter science and engineering disciplines This DMREF GOALI project will exploit a new design strategy that utilizes a localized phase transformation (LPT) phenomenon to disruptively improve the high-temperature creep performance of Ni-based superalloys. LPTs occur only at extended defects and are confined locally at these defects. By integrating sophisticated computational models, at multiple scales, highly advanced materials characterization techniques, and combinatorial and accelerated methods of materials processing and property evaluation, this project will (a) search the high-dimensional alloy composition space for the occurrence of LPT by high-throughput DFT Monte Carlo calculations, and validate the DFT predictions by novel combinatorial methods to rapidly produce alloys, coupled with advanced electron microscopy and atom probe tomography; (b) establish the connection between defect type (stacking fault, anti-phase boundaries, twins, dislocations and their networks) and the nature of LPT using phase field simulations with the DFT calculations as inputs; (c) quantitatively determine the effect of LPT on the operative deformation mechanisms and develop physics-based deformation models that capture these effects using a combination of the phase field method and a mechanism-sensitive crystal plasticity model, which will enable direct validation against polycrystalline creep experiments; and (d) employ novel processing routes to stabilize high dislocation/twin density microstructures by LPT, thereby providing a new strengthening mechanism for deployment to superalloys. The GOALI partner of this project, GE Research, will respond to alloy recommendations by providing high quality alloys in single crystal and polycrystal forms. Such an integrated research effort will raise significantly the state-of-the-art in the discovery and development of new superalloys and is expected to result in new science in alloy design. The focus on superalloys will have a marked impact on a broad range of advanced technological areas including aerospace, transportation and energy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.