Chemistry Project Abstract
INVESTIGATION INTO NICKEL - BASED HEUSLER ALLOYS FOR USE IN ACTUATORS
Presenter:
Zheyan Chen, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506; jennyc@imsa.edu
Mentor:
Professor Philip Nash, Director, Illinois Institute of Technology, Thermal Processing Technology Center, 10 W. 32nd St., Chicago, IL, 60616; 312-567-3056; nash@iit.edu
Abstract:
Smart materials, and the related area of smart structures and systems, will be the basis for many future technologies used in various industries. Research in smart materials is focused on developing technology to enhance ordinary objects by embedding sensors, processors, or actuators in them. Magnetostrictive materials change dimensions when exposed to a magnetic field. Although not necessarily magnetic in their individual elements, Heusler alloys of the form X2YZ exhibit magnetostrictive shape memory effects at certain temperatures. At high temperatures, these alloys exist as austenite phases. On cooling, the austenite transforms to a thermoelastic martensite. They undergo a two-stage disorder to order transition: from A2, a disordered body centered cubic lattice, to B2, a fairly ordered body centered cubic lattice, to L2 1, the fully ordered austenitic phase. The material recovers to its original shape when all the possible structures of the martensite revert back to the orientation of the austenitic memory phase. This project specifically looks at the magnetostrictive properties of two types of nickel based Heusler alloys of the forms Ni2MnX and Ni2AlX. A variety of techniques, including optical microscopy, scanning electron microscopy, X-ray diffraction analysis, 3D modeling, and differential thermal analysis were used. As actuators, these magnetostrictive alloys present a revolutionary way to introduce dynamics into mechanical systems.