Effects of alumina content on long-term high-temperature creep behavior of silica-based ceramic cores
LI Kaiwen
LIU Lirong
GU Xingxiao
DONG Jiasheng
JIANG Weiguo
Abstract：[Objective]With the gradual achievement of independent research and development of gas turbine engines,the research and development of turbine blades,known as the"jewel in the crown",have attracted much attention.A part of the gas turbine blades are hollow in structure,and the ceramic cores are the main components that form the hollow blade cavity structure.Due to the large size of the hollow blade,the high-temperature casting time is much longer,and this leads to an extension of the high-temperature holding time of the ceramic core.To ensure that the ceramic core meets the casting requirements of large-sized hollow blades,it is particularly important to consider the long-term high-temperature creep behavior of the ceramic core.Therefore,the effect of alumina content on the long-term high-temperature creep behavior of silica-based ceramic cores was investigated in this paper.[Methods]First,fused silica was selected as the matrix,and the silica-based ceramic cores with different alumina contents were prepared.After sintering at 1200℃,a creep test was conducted at 1500℃for 1 h using the suspension method,during which the creep deformation characteristics were observed and the deformation amount was measured.Scanning electron microscopy(SEM)was used to observe the fracture microstructures of the ceramic cores after creep at high temperature.X-ray diffraction(XRD)was used to analyze the phase compositions of the ceramic cores in different states.[Results]It is indicated that for the samples with 20%alumina,the least porosity and the highest relative cristobalite content were detected after sintering and subsequent 1500℃for 1 h heat treatment.When the alumina content is 10%,the lowest creep deformation amount is obtained.The reaction between alumina and silica at high-temperature promotes viscous flow sintering,which increases the creep deformation of the ceramic cores.[Conclusions]Adding alumina can promote the phase transformation from fused silica to cristobalite during the sintering process.After high-temperature holding,as the content of alumina increases,alumina participates in the reaction,forming the mullite phase,causing viscous flow sintering and increasing the creep deformation amounts of the ceramic cores.To obtain silica-based ceramic cores with high strength and excellent long-term creep properties,it is necessary to reasonably control the content of alumina.
Keywords：aluminasilica-based ceramic corecristobalitehigh-temperature creepcreep deformation amountfracture morphologyporosityviscous flow sintering
Publication Date：2026-01-25
Online Publishing Date：2026-03-17(First online date of this platform, not the publication date of the document)
Pages：6( 93-98 )