Combinatorial search of thermoelastic shape-memory alloys with extremely small hysteresis width

Area of Science:

• Materials Science
• Solid-State Physics
• Crystallography

Background:

• Reversibility of structural phase transformations is critical for applications such as shape-memory alloys (SMAs) and multiferroic oxides.
• A universal geometric nonlinear theory of martensite has been developed to predict transition reversibility based on crystal symmetry and phase compatibility.

Purpose of the Study:

• To verify the geometric nonlinear theory of martensite using a high-throughput approach.
• To establish a direct relationship between theoretical predictions and experimental observations of phase transition hysteresis.

Main Methods:

• Utilized the thin-film composition-spread technique for rapid mapping of lattice parameters and thermal hysteresis in ternary alloy systems.
• Applied high-throughput methods to systematically test the predictions of the martensite theory across various material compositions.

Main Results:

• Observed a direct correlation between material hysteresis and the middle eigenvalue of the transformation stretch tensor, confirming a key theoretical prediction.
• Identified a novel composition region in titanium-rich SMAs exhibiting promising characteristics for enhanced property control.

Conclusions:

• The geometric nonlinear theory of martensite accurately predicts the reversibility of structural phase transformations.
• The findings pave the way for designing materials with tailored properties by controlling phase transformation behavior, particularly in SMAs.