Pseudoelasticity of SrNi2P2 Micropillar via Double Lattice Collapse and Expansion

• 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 SrNi2P2 micropillar exhibits pseudoelasticity with a large maximum recoverable strain of similar to 14% under uniaxial compression via unique reversible structural transformation, double lattice collapse-expansion that is repeatable under cyclic loading. Its high yield strength (similar to 3.8 +/- 0.5 GPa) and large maximum recoverable strain bring out the ultrahigh modulus of resilience (similar to 146 +/- 19 MJ/m(3)), 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 thermomechanical actuation, even though the structural changes involved are completely different. Our work suggests that the discovery of a new class of high-performance ThCr2Si2-structured materials will open new research opportunities in the field of pseudoelasticity.

Subject headings

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Keyword

SrNi2P2

micropillar compression

pseudoelasticity

maximum recoverable strain

density functional theory

Publication and Content Type

ref (subject category)

art (subject category)