Effects of TiO₂ doping on microstructure and properties of directed laser deposition alumina/aluminum titanate composites

ABSTRACT

Al₂O₃-based composite ceramics have excellent high temperature performance and are ideal materials for preparing hot end components. However, poor fracture toughness and thermal shock resistance limit its applications. Based on the excellent low thermal expansion characteristics and thermal shock resistance of Al₂TiO₅ ceramic, different composition ratios of Al₂O₃/Al₂TiO₅ composite ceramics were prepared by directed laser deposition (DLD) technology. Effects of TiO₂ doping amount on microstructure and properties of the composite ceramics were investigated. Results show that α-Al₂O₃ phase is discretely distributed in the continuous aluminum titanate matrix when TiO₂ doping amount between 2 and 30 mol%. With the increase of TiO₂ doping amount, content of Al₂O₃ gradually decreases and its morphology changes from cellular to dendritic. When TiO₂ doping amount reaches 43.9 mol%, the microstructure transforms into fine Al₂TiO₅/Al₆Ti₂O₁₃ eutectic structure. Property test results show that Al₂O₃/Al₂TiO₅ composite ceramics have good comprehensive mechanical properties when TiO₂ doping amount between 2 and 6 mol%.

KEYWORDS:

• Additive manufacturing
• composite ceramics
• Al₂O₃/Al₂TiO₅
• microstructure
• properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Dongjiang Wu is a Professor of Mechanical Engineering, Dalian University of Technology. Mainly engaged in the research of laser beam and material interaction mechanism and additive manufacturing, especially in the field of ceramic-based materials, metal/ceramic composite functional gradient materials.

Yunfei Huang is a Master of Mechanical Engineering, Dalian University of Technology. Mainly engaged in the research of laser additive manufacturing of ceramics.

Fangyong Niu is an Assistant Researcher and Ph.D. of Mechanical Engineering, Dalian University of Technology. Mainly engaged in the research of laser additive manufacturing of ceramics, metals and composite materials.

Guangyi Ma is an Associate Professor of Mechanical Engineering, Dalian University of Technology. Mainly engaged in the research of laser additive manufacturing of ceramics, metals and composite materials.

Shuai Yan is a Ph.D. of Mechanical Engineering, Dalian University of Technology. Mainly engaged in the research of laser additive manufacturing of ceramics.

Chaojiang Li is a Research Fellow in the Department of Materials Science and Engineering, National University of Singapore. His research interests include additive manufacturing of ceramic and metal, and process monitoring.

Jun Ding is a Full Professor in the Department of Materials Science and Engineering, National University of Singapore. His research focuses on the development of starting materials for fabrication of multi-functional devices/structures of metal, ceramics, polymer and composite.

Additional information

Funding

This work was supported by China Postdoctoral Science Foundation [grant number No. 2017M620100, No. 2018T110215]; National Natural Science Foundation of China [grant number No. 51790172, No. 51805070, No. 51875075].