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Additively manufactured superelastic NiTi: a paradigm shift to eliminate heat treatment

October 05, 2018 | 11 a.m.
Nedderman Hall Room 203 | Seminar Flyer

Seminar Speaker

Narges Shayesteh, Ph.D.

Assistant Professor, Mechanical and Aerospace Engineering Department, UTA

DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING
Fall 2018 SEMINAR SERIES

Abstract:
Nowadays, shape memory alloys (SMAs), and in particular Nickel-Titanium alloys (i.e., NiTi or Nitinol), are widely used in biomedicine, and to a lesser extent in automotive, and aerospace industries. Thanks to their unique shape memory effect (SME) and superelasticity (SE), these alloys can recover a large deformation up to 8% through reversible phase transformations and provide light-weight actuation in low-profile devices. They also represent other favorable characteristics, such as biocompatibility, low stiffness (i.e., Modulus of elasticity), high damping capacity, and adequate corrosion resistance. It is well established that the thermomechanical response of NiTi depends on the crystal texture and microstructure features of the alloy. These features, in turn, are significantly affected by the thermal and mechanical (thermomechanical) treatment history applied to the material during the alloy development and device fabrication. These treatments are generally treated as trade secrets and are very know-how intensive. More specifically, heat treatment is frequently used to change microstructure and texture. Additively manufactured NiTi is no exception and the functionality of the parts fabricated using this method has been shown to change as the result of heat treatments. In this work, the influence of process parameters on the microstructure and texture of AM NiTi are summarized as the effect of heat treatment induced during the fabrication. The main goal of this research is to identify the relationship between the processing parameters to generate the desired microstructure and texture in AM fabricated NiTi. In the work conducted up to this point, it was found that it is possible to form a strong texture along the (001) orientation in the AM fabricated parts through adjusting the process parameters, and therefore creating a desirable pattern of heat transfer and the resulting in situ heat treatment during the fabrication.

Bio:
Dr. Narges Shayesteh Moghaddam completed her doctoral studies in Mechanical Engineering at The University of Toledo in June 2018 and joined UTA’s Mechanical and Aerospace Engineering department soon after. She has made original contributions to the field of mechanical engineering. Specifically, her specialized research has focused on additive manufacturing of functional devices. In a most recent project sponsored by NASA Glen Research Center, she fabricated high temperature shape memory alloys (HTSMAs) through additive manufacturing techniques for the first time. Dr. Shayesteh has published in prestigious, top-ranked journals in the field and has subsequently been cited extensively. She is also the author of 1 U.S. patent entitled “Methods, devices, and manufacture of the devices for musculoskeletal reconstructive surgery.” Dr. Shayesteh serves as editor and peer reviewer for top-ranked journals in the field. She also serves as a reviewer for grant funding organization Kentucky Science and Engineering Foundation (KSEF). Dr. Shayesteh is a member of Woman in 3D Printing Organization, the Honor Society of Phi Kappa Phi, the Society of Manufacturing Engineer (SME), and the American society of mechanical engineering (ASME). Continuing to advance the field through fundamental and applied research is of immeasurable importance because it leads to improvements in understanding novel materials and producing functional devices, which positively impacts 3D printing, biomedical research, aerospace engineering, and numerous other industries.