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Development of Strategies to Avoid Them
Materials Science and Engineering Seminar
Morteza Shaker Ardakani, PhD Candidate
Department of Materials Science and Engineering
Michigan Technological University
Abstract: Zinc based alloys were introduced in the last few years as new absorbable materials for biomedical implants due to their promising corrosion rate and biocompatibility. However, their poor mechanical strength and ductility, as well as susceptibility to creep and fatigue, restrict their usage in vascular scaffolding applications. The addition of Mg to Zn alloys as an alloying element has been studied in many laboratories, considering its well-known biocompatibility and improvement in the mechanical properties of Zn. Nevertheless, the mechanical instability, strain softening and strain rate sensitivity of the Zn-Mg binary alloys after extensive plastic deformation at room temperature are main concerns remained unsolved. These properties negatively affect the elongation to failure, creep and fatigue resistance of the Zn-Mg based alloys. This talk focuses on the deformation mechanism of Zn-Mg based alloy and the development of the strategies to solve the problems in the mechanical behavior of them for the stenting application. The mechanism of the mechanical instability of the in Zn-Mg based alloys and the effect of the additional alloying elements on it will be illustrated. The origin of the strain softening and strain rate sensitivity observed at the very fine-grained Zn structure will be presented. Finally, the effect of the post-deformation heat treatments on the extensively cold worked alloys, and consequently the impacts of the grain size and fraction of the secondary phase on the strain softening and strain rate sensitivity will be discussed.
Bio: Morteza Shaker Ardakani completed his BSc degree in Materials Science and Engineering, followed by MSc in Engineering Materials-Design and Selection in Iran from Sharif University of Technology. He worked as lecturer and metallography lab supervisor for two years. He also worked as melting expert in Chadormalu steel making plant in Iran for a few months. He joined Michigan Tech in the Fall of 2017 to pursue his PhD studying in SURFI team. His focus is understanding the fundamental of the mechanical behavior of Zn based alloys for the bioabsorbable implant applications under the guidance of Prof. Drelich.