Thermodynamically Guided Improvement of Fe-Mn-Al-Ni Shape-Memory Alloys

Area of Science:

• Materials Science
• Thermodynamics
• Metallurgy

Background:

• Shape-memory alloys (SMAs) exhibit unique functional properties.
• Tailoring pseudoelastic performance in Fe-Mn-Al-Ni SMAs is crucial for applications.
• Understanding microstructural influences on SMA behavior is essential.

Purpose of the Study:

• To utilize a microstructural informed thermodynamic model to tailor pseudoelastic performance.
• To reveal the influence of B2-ordered precipitates on austenitic stability and pseudoelastic response.
• To confirm the applicability of proposed models for predicting shape-memory capabilities.

Main Methods:

• Development and application of a microstructural informed thermodynamic model.
• Nanoindentation measurements.
• Incremental-strain tests under compressive loading.

Main Results:

• The stability and amount of B2-ordered precipitates significantly influence austenitic stability.
• Pseudoelastic response is directly correlated with microstructural features predicted by the model.
• Model predictions align with experimental nanoindentation and compressive loading results.

Conclusions:

• The proposed thermodynamic model accurately predicts shape-memory capabilities in Fe-Mn-Al-Ni alloys.
• Thermodynamic considerations enable guided enhancement of functional properties through alloy design.
• This approach represents a significant advancement in the development of shape-memory alloys.