The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powders

Abstract

CoCrMo and Ti6Al4V are widely used in medical, dental and 3D printing technology, allowing the accurate fabrication of geometrically complicated structures. In order to reduce the costs of printed objects, the reuse of powder is common daily practice. When using 3D printing technology, the direct impact of elevated temperatures and the influence of the laser beam may change the properties of the powder when it is reused, thus affecting the final properties of the printed object. The main aim of the present study was to investigate the impact of reused powder on the mechanical, microstructural and electrochemical properties of 3D printed objects. 3D printed objects fabricated from virgin and reused powder of both alloys were analyzed by metallographic observation, computed tomography, XRD and electrochemical methods. The main finding of the study was that the use of reused powder (recycled 3 times) does not detrimentally affect the mechanical and corrosion integrity of 3D printed CoCr and Ti6Al4V alloys, especially for the purpose of applications in dentistry.

Characterization, preparation, and reuse of metallic powders for laser powder bed fusion: a review

“…The mechanical properties of L-PBF Ti and Ti alloys experience variations due to composition change. An increasing trend is observed for the hardness of samples fabricated with reused Ti6Al4V powders [241,243,248], which is linked to the elevated oxygen content in an interstitial solid solution, since it may modify the lattice parameters or c/a ratio, influencing the dislocation glide and causing an increase in the strength but a reduction in ductility [249]. In terms of tensile properties, most of the studies [183,242,243] show that the YS and UTS increase for samples printed with reused Ti6Al4V powders.…”

“…The pick-up of oxygen and nitrogen of Ti and Ti alloy powders causes various evolution trends in the densification of printed parts among different researches [203,204,242,245,248]. The inconspicuous difference in densification for samples printed with virgin and reused powders is commonly observed.…”

“…(c) EBSD map and phase distribution of virgin (i and ii) and reused (iii and iv) samples. Reproduced from [248], with permission from Springer Nature. (d) Tensile properties, including yield strength (i) and elongation (ii).…”

The Effects of Reusing Cobalt-Chromium Alloy Powder on Its Mechanical Properties and Grain Size: An In Vitro Study

“…1 One of the advantages is the possibility of reusing alloy powders. 2 As a result, this method is much more cost-effective compared to other manufacturing techniques. The reusability of alloy powder is also important from an environmental sustainability perspective, as almost no residual material is formed.…”

“…This deforms the spherical shapes of the particles, which become contaminated with gases (nitrogen, oxygen, and moisture), resulting in altered flow properties. 2,9,10 The effect of these changes in alloy powder was investigated in previous studies. However, most of the studies were conducted using alloy powders that are not used for building dental restorations.…”