Laser powder bed fusion additive manufacturing of NiTi shape memory alloys: a review

Abstract

NiTi alloys have drawn significant attention in biomedical and aerospace fields due to their unique shape memory effect (SME), superelasticity (SE), damping characteristics, high corrosion resistance, and good biocompatibility. Because of the unsatisfying processabilities and manufacturing requirements of complex NiTi components, additive manufacturing technology, especially laser powder bed fusion (LPBF), is appropriate for fabricating NiTi products. This paper comprehensively summarizes recent research on the NiTi alloys fabricated by LPBF, including printability, microstructural characteristics, phase transformation behaviors, lattice structures, and applications. Process parameters and microstructural features mainly influence the printability of LPBF-processed NiTi alloys. The phase transformation behaviors between austenite and martensite phases, phase transformation temperatures, and an overview of the influencing factors are summarized in this paper. This paper provides a comprehensive review of the mechanical properties with unique strain-stress responses are also explained, which comprise tensile mechanical properties, thermomechanical properties (e.g., critical stress to induce martensite transformation, thermo-recoverable strain, and superelasticity strain), damping properties and hardness. Moreover, several common structures (e.g., a negative Poisson’s ratio structure and a diamond-like structure) are considered, and the corresponding studies are summarized. It illustrates the various fields of application, including biological scaffolds, shock absorbers, and driving devices. In the end, the paper concludes with the main achievements from the recent studies and puts forward the limitations and development tendencies in the future.

Revealing precipitation behavior and mechanical response of wire-arc directed energy deposited Mg-Gd-Y-Zr alloy by tailoring aging procedures

“…As is well-known, it is the complex thermal history of the AM process that contributes to the unique microstructure [43][44][45][46][47][48][49]. The microstructure of GW-series alloys prepared by conventional casting and AM processes such as wire-arc DED and L-DED is compared in figure 16.…”

Laser-based bionic manufacturing

“…NiTi alloy stands out as one of the most frequently employed smart materials, owing to its distinctive functional characteristics [115,116]. Leveraging laser material manufacturing technology for the creation of intricate shapes, and controlled deformation accuracy of nickel-titanium alloy enjoys unparalleled advantages over traditional methods, providing an ideal means for manufacturing intelligent metal devices [117]. The bionic crab claw structures prepared by utilizing the flexible building strategy of LPBF technology and the track-by-track and layer-by-layer processing modes have strong toughness and damage resistance [118].…”

Effect of solution treatment on the microstructure, phase transformation behavior and functional properties of NiTiNb ternary shape memory alloys fabricated via laser powder bed fusion in-situ alloying

“…Laser powder bed fusion (L-PBF), a layer-wise additive manufacturing technology, is capable of producing complex NiTi parts, such as scaffolds [16][17][18][19]. L-PBF could also act as an in-situ alloying (ISA) method when using blended powders, which has been applied in the development of Ti- [20,21], Albased [22,23] and high entropy alloys [24].…”