Pseudoelasticity of SrNi<sub>2</sub>P<sub>2</sub> Micropillar via Double Lattice Collapse and Expansion.

Xiao, Shuyang; Borisov, Vladislav; Gorgen-Lesseux, Guilherme; Rommel, Sarshad; Song, Gyuho; Maita, Jessica M; Aindow, Mark; Valentí, Roser et al. · Nano Lett · 2021

basic_science · Level V

Where this comes from

Abstract

The maximum recoverable strain of most crystalline solids is less than 1% because plastic deformation or fracture usually occurs at a small strain. In this work, we show that a SrNi<sub>2</sub>P<sub>2</sub> micropillar exhibits pseudoelasticity with a large maximum recoverable strain of ∼14% under uniaxial compression via unique reversible structural transformation, double lattice collapse-expansion that is repeatable under cyclic loading. Its high yield strength (∼3.8 ± 0.5 GPa) and large maximum recoverable strain bring out the ultrahigh modulus of resilience (∼146 ± 19 MJ/m<sup>3</sup>), a few orders of magnitude higher than that of most engineering materials. The double lattice collapse-expansion mechanism shows stress-strain behaviors similar to that of conventional shape-memory alloys, such as hysteresis and thermo-mechanical actuation, even though the structural changes involved are completely different. Our work suggests that the discovery of a new class of high-performance ThCr<sub>2</sub>Si<sub>2</sub>-structured materials will open new research opportunities in the field of pseudoelasticity.