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Research Article | Open Access

Microstructure and mechanical properties of melt-grown alumina-mullite/glass composites fabricated by directed laser deposition

Dake ZHAODongjiang WUJing SHIFangyong NIU( )Guangyi MA
Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China
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Graphical Abstract


Melt-grown alumina-based composites are receiving increasing attention due to their potential for aerospace applications; however, the rapid preparation of high-performance components remains a challenge. Herein, a novel route for 3D printing dense (< 99.4%) high-performance melt-grown alumina-mullite/glass composites using directed laser deposition (DLD) is proposed. Key issues on the composites, including phase composition, microstructure formation/evolution, densification, and mechanical properties, are systematically investigated. The toughening and strengthening mechanisms are analyzed using classical fracture mechanics, Griffith strength theory, and solid/glass interface infiltration theory. It is demonstrated that the composites are composed of corundum, mullite, and glass, or corundum and glass. With the increase of alumina content in the initial powder, corundum grains gradually evolve from near-equiaxed dendrite to columnar dendrite and cellular structures due to the weakening of constitutional undercooling and small nucleation undercooling. The microhardness and fracture toughness are the highest at 92.5 mol% alumina, with 18.39±0.38 GPa and 3.07±0.13 MPa·m1/2, respectively. The maximum strength is 310.1±36.5 MPa at 95 mol% alumina. Strength enhancement is attributed to the improved densification due to the trace silica doping and the relief of residual stresses. The method unravels the potential of preparing dense high-performance melt-grown alumina-based composites by the DLD technology.


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Journal of Advanced Ceramics
Pages 75-93
Cite this article:
ZHAO D, WU D, SHI J, et al. Microstructure and mechanical properties of melt-grown alumina-mullite/glass composites fabricated by directed laser deposition. Journal of Advanced Ceramics, 2022, 11(1): 75-93.








Web of Science






Received: 07 February 2021
Revised: 19 June 2021
Accepted: 08 July 2021
Published: 12 November 2021
© The Author(s) 2021.

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