Investigation of microstructure evolution and properties in silica‐based ceramic cores with alumina as a mineralizer

In this work, silica‐based ceramic cores with alumina as a mineralizer were prepared via an injection molding method, and the effects of alumina on the microstructural evolution and properties at 1450°C (simulating the process of equiaxed castings) and 1550°C (simulating the process of columnar/sing...

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Bibliographic Details
Published in:International journal of applied ceramic technology 2023-05, Vol.20 (3), p.2009-2018
Main Authors: Pan, Zhiping, Guo, Jianzheng, Li, Shuangming, Xiong, Jiangying
Format: Article
Language:English
Subjects:
Alumina
Aluminum oxide
Ambient temperature
Casting
Castings
Ceramics
Cristobalite
Crystallization
Devitrification
Evolution
Flexural strength
Fused silica
Injection molding
Microstructure
properties
Single crystals
turbine blade casting
Turbine blades
Viscous flow
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Summary:In this work, silica‐based ceramic cores with alumina as a mineralizer were prepared via an injection molding method, and the effects of alumina on the microstructural evolution and properties at 1450°C (simulating the process of equiaxed castings) and 1550°C (simulating the process of columnar/single crystal castings) were investigated. It was found that alumina promoted the cristobalite crystallization of fused silica refractory during sintering but inhibited the devitrification rate in the subsequent heating. The flexural strength of silica‐based ceramic cores at an ambient temperature and 1450°C improved with an increasing alumina content, whereas the opposite trend appeared at 1550°C. The creep resistances of silica‐based cores were improved significantly and then slightly deteriorated with an increasing alumina content from 5% to 20%, depending on the competition effects of alumina hindering the viscous flow of liquid silica (favorable), but suppressing the devitrification rate (unfavorable). The results of this work show that silica‐based cores need to follow different compositional design principles for equiaxed and columnar/single‐crystal turbine blade castings.
ISSN:1546-542X
1744-7402
DOI:10.1111/ijac.14291