3D and 4D Printing of Complex Structures of FeMnSi‐Based Shape Memory Alloy Using Laser Powder Bed Fusion

The additive manufacturing of shape memory materials, commonly known as 4D printing, facilitates the achievement of a complex 3D structure that possesses a temperature‐dependent shape change functionality. Herein, it is demonstrated that complex 3D structures of Fe‐based shape memory alloys (Fe‐SMAs) can be produced through a 3D printing process of laser powder bed fusion (L‐PBF). The 3D printed Fe‐SMA shows good mechanical properties with much higher strength and stiffness than those in shape memory polymers. The printed Fe‐SMAs manifest shape recovery behavior, demonstrating that material‐inherent functional behaviors can be combined with the functionalities of the complex 3D structures to facilitate shape morphing, self‐healing, and auxetic behavior and to achieve a lattice structure with extraordinary specific strength.