Thermal hysteresis is a critical design parameter for shape memory materials, particularly for shape memory ceramics, where high hysteresis may be associated with catastrophic cracking upon transformation. A direct framework for predicting hysteresis from the atomistic level does not exist, so proxies such as the interfacial compatibility condition, ${\lambda }_2$, are used for the computational design of shape memory materials. In this paper, we introduce a framework that directly links interfacial compatibility to the energy barriers encountered during the phase transformation. We derive these barriers using adjusted Nudged Elastic Band calculations for two prototypical shape memory systems: zirconia-ceria and NiTi. Although our method does not explicitly simulate the martensite-austenite interface, we demonstrate that the structural pathway followed during the transformation samples the same atomistic structures as that interface. Furthermore, we show that the different correlations observed between the two material classes are fundamentally linked to differences in their shear moduli. These results help explain why our results reveal a strong correlation between interfacial compatibility and the transformation energy barriers: the atomic distortions required to effect the transformation are present whether at interfaces or not, and are accommodated elastically. This approach establishes a computationally efficient, quantum-accurate, method for determining energy barriers directly linked to thermal hysteresis, facilitating the design of resilient shape memory materials.

Close

PrevNext

View figure in article

• Phase transitions
• Shape memory effect
• Deep potential molecular dynamics
• Machine learning