Origami Metamaterials Based on Low-Melting-Point Alloy Phase Transition: Breaking the Trade-Off Between Reusability...

Mechanical metamaterials provide a promising platform for designing energy-absorbing materials. However, the trade-off between reusability and energy absorption quality limits the overall performance of existing energy-absorbing metamaterials. To address this challenge, an origami metamaterial based on the low-melting-point alloy phase transition is proposed in this study, constructed by integrating a low-melting-point alloy skeleton into an elastomeric shell. In terms of performance, the metamaterial achieves an energy absorption capacity of 41.5 kJ·m^{- 2}, a crushing force stability of 0.838, and a reusability ratio of 97.8%. This outstanding overall performance stems from a multilevel synergistic design. At the material level, plastic deformation of the metal skeleton provides high energy absorption. Meanwhile, the heat-induced solid-liquid phase transition of the low-melting-point alloy, together with the hyperelasticity of the elastomeric shell, enables high structural recoverability. At the unit-cell level, tailoring the geometric parameters yields a stable force response, and the diamond origami configuration further enhances energy absorption quality. At the multi-cell system level, eliminating deformation coupling between layers significantly enhances the deformation mode stability of multilayer metamaterials, thereby extending the effective compression stroke. Overall, the metamaterial simultaneously achieves high-quality energy absorption and high reusability, showing great potential for engineering applications that require repeated energy absorption.