GOALI: Understanding Deformation Processing in Advanced Alloys

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Shape memory alloys are multifunctional materials that undergo an reversible phase transformation when exposed to heat or external load. These transformations can led to useful properties, and their behavior can be controlled if the relationships between the transformational and fine particles dispersed throughout the material can be understood. A class of shape memory alloys comprised of nickel, titanium and niobium (NiTiNb) exhibit structures with unique constituent morphologies. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports research seeking to couple thermal and mechanical deformation processing and examine and understand the resulting Nb particle interactions with the underlying phase transformation and deformation mechanisms. The industrial partner specializes in fabrication of NiTiNb materials and employs laser-based machining techniques for post-processing without compromising the shape memory behavior. The approaches and findings can extend to deformation processed shape memory alloys with insoluble third elements in general. Fundamental interrelationships this research establishes will unlock the full potential of manufacturing multifunctional shape memory materials to tune performance for novel deployable structures. The success of this research will advance processing multifunctional alloys to commercialization as next-generation materials in broad ranging applications from biomedical implants to unmanned vehicles that benefit the U.S. economy and society. Furthermore, education and outreach programs will closely integrate the technical research. Programs designed for high school, undergraduate, and graduate levels will deepen the engagement of minorities and underrepresented groups in academic disciplines of science, technology, engineering, and mathematics. This small business industry-university collaborative GOALI project will investigate the underlying physical martensitic phase transformation (MT) mechanism of a novel shape memory material response referred to as strain-induced austenite (SIA) in a class of ternary NiTi-based shape memory alloys (SMAs) with an insoluble third element Nb. A consequence of ternary alloying and thermo-mechanical deformation processing is a micro-/nano-structured Nb particle constituent morphology.The collaborative team will (1) systematically vary thermo-mechanical processing and post-processing parameters of deployable structures; (2) conduct x-ray, electron, and optical microscopy characterizations of micro-/nano-constituent sizes, spacing, and coherency as well as grain size and texture; (3) undertake multi-scale thermo-mechanical experiments that determine multifunctional material properties and structural response; (4) establish quantitative and qualitative relationships between processing, microstructure and multifunctionality.