Institute of Materials Research
Topic
Study of shape memory effect stability in Ni2FeGa microwires
PhD. program
Advanced Materials
Year of admission
2024
Name of the supervisor
doc. Ing. Ondrej Milkovič, PhD.
Contact:
Receiving school
Prírodovedecká fakulta UPJŠ
Annotation
The ferromagnetic Heusler alloy Ni2FeGa has broad application potential in sensors and actuators due to the combination of its magnetic properties and the existence of the shape memory phenomenon (SMP). The temperature range of the thermo-elastic phase transformation of the SMP can be controlled by varying the chemical composition of the alloy, more precisely by the changing atomic configuration of the ordered parent phase. While the equilibrium chemical composition of the ordered phase has a transformation temperature of around 50 K, it is possible to shift the transformation above the temperature of 300 K by supersaturating the ordered phase. The pilot experiment showed that the alloy in the form of microwires has, due to its thickness (< 30 m), a unique resistance to cyclic transition through the temperature phase transformation region. Changes in material structure and properties were not observed after more than 106 cycles. The topic of the dissertation is focused on the study of the Heusler alloy shape memory effect and the properties concerning their structure and the form of the prepared alloy. The work is focused on determining the thermal and mechanical stability of the ordered parent phase and justifying the effects on the transformation temperature of the produced microwires.