The Influence of Microstructure on the Flexural Properties of 3D Printed Zirconia Part via Digital Light Processing Technology.

Boran Wang,Ali Arab,Jing Xie,Pengwan Chen

doi:10.3390/ma15041602

Abstract

In recent years, additive manufacturing of ceramics is becoming of increasing interest due to the possibility of the fabrication of complex shaped parts. However, the fabrication of a fully dense bulk ceramic part without cracks and defects is still challenging. In the presented work, the digital light processing method was introduced for fabricating zirconia parts. The flexural properties of the printed zirconia were systematically investigated via a three-point bending test with the digital image correlation method, scanning electron microscopy observation and fractography analysis. Due to the anisotropy of the sample, the bending deformation behaviors of the zirconia samples in the parallel and vertical printing directions were significantly different. The flexural strength and the related elastic modulus of the samples under vertical loading were higher than that of the parallel loading, as the in-plane strength is higher than that of the interlayer strength. The maximum horizontal strain always appeared at the bottom center before the failure for the parallel loading case; while the maximum horizontal strain for the vertical loading moved upward from the bottom center to the top center. There was a clear dividing line between the minimum perpendicular strain and the maximum perpendicular strain of the samples under parallel loading; however, under vertical loading, the perpendicular strain declined from the bottom to the top along the crack path. The surrounding dense part of the sintered sample (a few hundred microns) was mainly composed of large and straight cracks between printing layers, whereas the interior contained numerous small winding cracks. The intense cracks inside the sample led to a low flexural property compared to other well-prepared zirconia samples, which the inadequate additive formulations would be the main reason for the generation of cracks. A better understanding of the additive formulation (particularly the dispersant) and the debinding-sintering process are necessary for future improvement.

Highlights

Zirconia (ZrO2) is widely used as an implant due to its excellent biocompatibility, mechanical properties, and satisfying aesthetics [1,2]. It has three phases: cubic ZrO2 (c-ZrO2) exists at temperatures higher than 2370 ◦C; tetragonal ZrO2 (t-ZrO2) exists between 1170 and 2370 ◦C, and when the temperatures are lower than 1170 ◦C, a phase transition from t- ZrO2 to monoclinic ZrO2 (m-ZrO2) occurs
It has been of great interest to use the additive manufacturing (AM) [3,4] technique in the ceramic industry to sidestep the conventional manufacturing challenges and save potentially up to 80% of the fabrication cost of the ceramic parts [5]
Foslruprrriynrtienvgeaplreodcesshseianrg-.thinning fluid behavior, indicating the slurry was appropriate for printing processing

Summary

Introduction

Zirconia (ZrO2) is widely used as an implant due to its excellent biocompatibility, mechanical properties, and satisfying aesthetics [1,2]. The in-plane strength of printing layers determines the deformation behavior of samples under vertical loading.

Results

Conclusion