Metallic 4D Printing of Laser Stimulation

Abstract

4D printing of metallic shape‐morphing systems can be applied in many fields, including aerospace, smart manufacturing, naval equipment, and biomedical engineering. The existing forming materials for metallic 4D printing are still very limited except shape memory alloys. Herein, a 4D printing method to endow non‐shape‐memory metallic materials with active properties is presented, which could overcome the shape‐forming limitation of traditional material processing technologies. The thermal stress spatial control of 316L stainless steel forming parts is achieved by programming the processing parameters during a laser powder bed fusion (LPBF) process. The printed parts can realize the shape changing of selected areas during or after forming process owing to stress release generated. It is demonstrated that complex metallic shape‐morphing structures can be manufactured by this method. The principles of printing parameters programmed and thermal stress pre‐set are also applicable to other thermoforming materials and additive manufacturing processes, which can expand not only the materials used for 4D printing but also the applications of 4D printing technologies.

4D printing for biomedical applications

“…One of the major challenges of SLM is the generation of large, anisotropic internal residual stresses that can introduce defects within the final printed part and compromise material properties. 174,175 While often perceived as a detriment, laser-induced thermal stresses can be strategically employed to drive self-deformation either during the printing process or post-printing, by releasing accumulated thermal stresses 163 (refer Fig. 3(d)).…”