Sid Pathak: Shape memory alloys

Title

Additive Manufacturing of Functional Hierarchical Shape Memory Alloy Structures

Mentor

Sid Pathak

Department

Chemical and Materials Engineering

Biosketch

I plan to integrate education and research to provide a multitude of enrichment opportunities for the undergraduate students to gain exposure to advanced research in the areas of experimental materials science and mechanics. Students participating in this project will be trained in research methods structural and chemical analysis (X Ray Diffraction, Scanning Electron Microscopy, and Transmission Electron Microscopy), synthesis, and nano-mechanical testing. Select students will also have the opportunity to present their work at international conferences, as well as publishing their work in peer-reviewed journals, depending on the quality of work performed.

I have mentored multiple undergraduates at UNR, both from programs such as the McNair Scholars Program, underrepresented students (3 female and one Hispanic), as well as regular undergraduates. Undergraduate students in my lab have gone on to receive a number of fellowships and scholarships, including the 2018-19 Nevada NASA Space Grant Consortium Undergraduate scholarship, 2018 TMS Structural Materials Division (SMD) Undergraduate Scholarship, 2017 Nevada Undergraduate Research Award and the Nevada National Science Foundation's Experimental Program to Stimulate Competitive Research (NSF EPSCoR) 2016 Academic Year Undergraduate Research Opportunity Program (UROP) fellowship. 

For more deatils Check out our webpage at wolfweb.unr.edu/homepage/spathak

Project Overview

In this project we will synthesis and engineer lamellar shape memory alloy (SMA) smart materials and demonstrate the capacity of laser directed energy deposition (LDED) additive manufacturing (AM) for tuning smart material assemblies for variable stiffness during vibration or impact events. LDED is advantageous for tailoring composition using elementally blended powder feedstock; for joining SMAs to dissimilar materials; and for faster build-up of larger structures. Interfaces between the layers and lamella are in direct competition with the martensitic morphology to drive a tailored macroscopic mechanical behavior. We develop materials engineering approaches informed by novel characterization tools to establish critical understandings of the interplay between the geometrical and microstructural hierarchy.

The proposed project will consist of integrated AM-SMA fabrication informed by multi-scale characterization. 1) LDED AM of Lamellar Shape Memory Alloy Structures (LSMAS): The LSMAS is composed of variable architecture with alternating SMA and non-SMA or differential composition lamellar subunit thickness dimensions on the order of micron - cm. 2) Scalable Thermo-Mechanical and Microstructure Characterization Strategies, complimentary nano-/micro-/meso-scale tests will be designed to interrogate the competition between microstructure and geometrical size effects on the martensitic transformation morphology and inherent reversibility. Our novel multi-scale deformation measurements are expected to (a) correlate performance of smallest geometrical/microstructural subunit to the multifunctional performance of the LSMAS, and (b) establish scale-up relationships correlating geometrical size effects with microstructure-shape memory transformation relationships.