Elastocaloric effect in strain glass alloys fabricated by laser-additive manufacturing

The elastocaloric effect (eCE) refers to a reversible thermal response under external stress. Doping stress-carrying defects, such as small-sized precipitates, to introduce strain glass transition in Ni-Ti alloys can broaden the operating temperature range of the eCE. In this work, Ni₅₂Ti₄₈ strain glass alloy was fabricated via laser-directed energy deposition, which provides a high cooling rate within millimeter-scale melt pools and enables the formation of fine-scale precipitates. These precipitates introduce heterogeneous stress fields that induce a strain glass transition, as evidenced by frequency-dependent dips in the storage modulus and the absence of significant exothermic/endothermic peaks in heat flow curves. An adiabatic temperature change of +10.9 K during loading and − 9.6 K upon unloading was observed. Both the elastocaloric effect and quasi-linear superelasticity (SE) are maintained across a temperature range from 233 K to 373 K.