From defect control to mechanical enhancement: A pathway via X-ray computed tomography for vat photopolymerization additive manufactured Al₂O₃ ceramics

TY - JOUR

T1 - From defect control to mechanical enhancement

T2 - A pathway via X-ray computed tomography for vat photopolymerization additive manufactured Al2O3 ceramics

AU - Zhang, Keqiang

AU - Meng, Qiaoyu

AU - Qu, Zhaoliang

AU - He, Rujie

N1 - Publisher Copyright: © 2026 Elsevier B.V.

PY - 2026/3/20

Y1 - 2026/3/20

N2 - The printing process is the most critical step in the vat photopolymerization (VPP) additive manufacturing of ceramics, as the formation of internal defects can significantly compromise the mechanical properties and structural integrity. However, conventional research methodologies are insufficient for the quantitative characterization of defects and are even inadequate for the effective control of defect formation. This study systematically investigates the printing process for fabricating high-performance Al2O3 ceramics, with a focus on understanding and controlling defects. An orthogonal experiment was designed to investigate the effects of three critical factors on the mechanical properties and relative density of the Al2O3 ceramic sintered body. The results showed that slicing thickness exerted the most significant influence on flexural strength, followed by irradiance, while exposure time had the least impact. The optimal parameter combination was identified as 12000 µW/cm2, 4 s, 100 µm, respectively. Internal defects in both green and sintered body and their formation mechanisms were 3D quantitatively characterized using X-ray computed tomography (X-CT). X-CT analysis revealed the presence of pore defects in the green body, while both pore and delamination defects were identified in the sintered body. Appropriate slicing thickness enhances interlayer bonding by facilitating adequate secondary photopolymerization, which significantly reduces delamination defects and controls their formation. This work establishes X-CT as a powerful tool for non-destructive analysis in additive manufactured ceramic.

AB - The printing process is the most critical step in the vat photopolymerization (VPP) additive manufacturing of ceramics, as the formation of internal defects can significantly compromise the mechanical properties and structural integrity. However, conventional research methodologies are insufficient for the quantitative characterization of defects and are even inadequate for the effective control of defect formation. This study systematically investigates the printing process for fabricating high-performance Al2O3 ceramics, with a focus on understanding and controlling defects. An orthogonal experiment was designed to investigate the effects of three critical factors on the mechanical properties and relative density of the Al2O3 ceramic sintered body. The results showed that slicing thickness exerted the most significant influence on flexural strength, followed by irradiance, while exposure time had the least impact. The optimal parameter combination was identified as 12000 µW/cm2, 4 s, 100 µm, respectively. Internal defects in both green and sintered body and their formation mechanisms were 3D quantitatively characterized using X-ray computed tomography (X-CT). X-CT analysis revealed the presence of pore defects in the green body, while both pore and delamination defects were identified in the sintered body. Appropriate slicing thickness enhances interlayer bonding by facilitating adequate secondary photopolymerization, which significantly reduces delamination defects and controls their formation. This work establishes X-CT as a powerful tool for non-destructive analysis in additive manufactured ceramic.

KW - AlO

KW - Defect

KW - Mechanical Property

KW - Vat Photopolymerization

KW - X-CT

UR - https://www.scopus.com/pages/publications/105032059736

U2 - 10.1016/j.jallcom.2026.187209

DO - 10.1016/j.jallcom.2026.187209

M3 - Article

AN - SCOPUS:105032059736

SN - 0925-8388

VL - 1059

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

M1 - 187209

ER -