Relating the Shape Memory Effect to Size of Additively Manufactured NiTi Alloy by Optimizing Full-Field Strain Analysis
Open Access
Author:
Schwarz, Jackson
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Reginald F Hamilton, Thesis Supervisor Joseph Paul Cusumano, Thesis Honors Advisor
Keywords:
shape memory alloy digital image correlation superelasticity nitinol full field strain analysis NiTi additive manufacturing
Abstract:
Shape memory alloys are a special class of materials that have a unique ability to “remember” their previous shape when they are pulled and stretched well beyond the ~1% recoverable deformation of ductile metals. Recovery via unloading is the superelastic SMA response and recovery via heating is referred to as shape memory effect SMA response. Processing of SMAs is designed to tune the composition and microstructure length scales to customize the shape memory responses for practical applications in aerospace and automotive to biomedical devices. Understanding how interactions between the underlying shape memory transformation mechanism and the SMA microstructure control the shape memory responses requires full-field (localized and pseudo-pointwise) micro-scale deformation measurements to supplement macro scale thermo-mechanical experimentation. This thesis project employs digital image correlation (DIC) analysis for full-field strain analysis. DIC analysis parameters are systematically varied for refining the local strain field contours resulting from the shape memory transformation morphology evolving within and interacting with different structural length scales. The research provides insights into optimizing DIC for scrutinizing deformation mechanisms interacting with different microstructure length scales.
