ABSTRACT
Nitinol is a smart alloy capable of recovering severe inelastic deformation by means of reversible solid phase transformation. This so-called shape-memory behavior has enabled innovative applications of nitinol in various fields, including aerospace and automotive engineering, seismic hazard mitigation, flexible robotics, and biomechanics. In this talk, I present recent work by our research group in relation to modeling porous nitinol and the fabrication of architected nitinol lattices by means of laser powder-bed fusion (LPBF). With regard to modeling, the Zaki-Moumni (ZM) model for shape memory alloys is generalized to account for the presence and nucleation of incidental cavities, similar to those observed in near-dense nitinol fabricated using powder bed methods. The ZM model is further utilized to estimate the effective mechanical and functional properties of a variety of architected nitinol topologies acting as standalone structures or as reinforcement in two-phase composites. I then proceed to sharing results and observations relating to the fabrication of dense and architected nitinol by LPBF and the characterization of its phase transformation temperatures and surface properties.
SPEAKER’S BIO
Wael Zaki is Professor and Associate Chair of Mechanical Engineering, and Theme Leader within the ADAM research center at Khalifa University. He obtained his Habilitation degree from Pierre and Marie Curie University (Paris VI, now part of Sorbonne University) in 2014, and his Ph.D. and M.Sc. degrees in solid mechanics from Ecole Polytechnique in 2006 and 2003, respectively. After completing a short postdoctoral appointment at ENSTA-
ParisTech, Dr. Zaki joined Henri Tudor Research Center in Luxembourg as a research & development engineer. He then joined the department of Mechanical Engineering at Khalifa University in 2010. Dr. Zaki attracted, as PI or Co-I, more than 5.5 million USD in competitive research grants, of which more than 4 million USD are for projects he directly leads. Dr. Zaki’s research interest is in the broad area of continuum mechanics applied to inelastic solids, with emphasis on computational inelasticity, fatigue, and shape memory alloys. His current work deals with 3D and 4D printing of a range of materials, including shape memory alloys and architected metamaterials. Dr. Zaki was included in Stanford’s list of top 2% scientists for the years 2019, 2020 and 2021, and was accredited as high-end foreign expert by the State Administration of Foreign Experts Affaires, China, in 2016.
