Determination of Thin NiTi Wires' Mechanical Properties during Phase Transformations

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics

Background:

• Industry 4.0 and the Internet of Things drive demand for autonomous smart materials.
• Shape-memory alloys, particularly nickel-titanium (NiTi), are key smart materials with sensor and actuator capabilities.
• Understanding NiTi alloy behavior under thermal and mechanical loads is essential for advanced applications.

Purpose of the Study:

• To investigate the influence of phase transformation on the mechanical properties of thin NiTi alloy wires.
• To analyze the relationship between heating current, generated force, and displacement in NiTi wires.
• To assess the impact of surface inhomogeneity on thermographic temperature measurements of NiTi wires.

Main Methods:

• Experimental analysis of thin NiTi alloy wires (Flexinol by DYNALLOY).
• Controlled heating current application to induce phase transformation and measure displacement and force.
• Thermographic temperature measurement during heating.
• Analysis of surface inhomogeneity effects on measurement accuracy.

Main Results:

• Maximum wire displacement is directly correlated with the applied heating current.
• Transformation dynamics exhibit a clear dependence on heating current values.
• Surface inhomogeneity of NiTi wires can affect the accuracy of thermographic measurements.

Conclusions:

• Heating current is a critical parameter controlling the performance of NiTi shape-memory alloy wires.
• Accurate temperature monitoring is vital, and surface characteristics of NiTi wires must be considered for precise measurements.
• These findings contribute to the effective design and application of NiTi smart materials in autonomous systems.