Use of 4D-printing and shape memory alloys to fabricate customized metal jewels with functional properties

Abstract

Purpose This paper aims to examine customized NiTi jewels with functional properties fabricated through four-dimensional (4D)-printing. Design/methodology/approach Two opened rings are fabricated through selective laser melting starting from 55.2Ni-Ti (wt.%) micrometric powder. After the additive process the two rings present the one-way shape memory effect (OWSME). A specific training is accomplished on one of the two printed rings to promote the two-way shape memory effect (TWSME). Both the samples, namely, the rings, respectively, presenting the OWSME and TWSME property, follow a series of post-processing routes to improve the surface finish. Furthermore, a thermal treatment at high temperature is used to create a thin colored oxide layer on the sample surface. Findings Results show that the change of shape owing to the OWSME and TWSME properties allows the customized 4D-printed rings to be adaptable to environmental changes such as load and temperature variations. This adaptability improves comfort and fit of the jewels. Originality/value To the best of the authors’ knowledge, in this work, first cases of additively manufactured NiTi jewels are reported to propose innovative solutions in the design and processing industry of jewels.

A Comprehensive Review of 4D Printing: State of the Arts, Opportunities, and Challenges

“…The researchers proposed using 4D printing technology to fabricate gloves that used for surgical applications. Nespoli et al fabricated personalized 4D-printed rings using SLM and shape-memory alloys as materials [340]. Although the rings were exposed to environmental changes, the printed rings fit and were comfortable, showing an improvement in the adaptability of jewelry.…”

4D printing: interdisciplinary integration of smart materials, structural design, and new functionality

“…Shape memory alloys (SMAs) are a category of metallic alloys capable of recovering back to their original shape upon exposure to certain external stimuli, such as temperature and tensile loading [39]. One of the most common 4D-printed SMAs is temperature-responsive NiTi alloys fabricated through the selective laser melting (SLM) technique (table 1) [90][91][92]. Very recently, Kim et al fabricated complex 3D structures with temperature-responsiveness, using Fe-Mn-Si-based SMAs fabricated through the laser powder bed fusion (L-PBF) technique, which exhibited high strength and stiffness [54].…”