【摘要】 本文将光固化成形技术和凝胶注模成形技术集成在一起,间接自由成形了带有收缩-扩张形气膜孔空心涡轮叶片整体式陶瓷铸型.通过建立收缩-扩张形气膜孔型芯干燥收缩受阻模型,推导了临界干燥收缩率计算公式,实验研究了凝胶注模成型坯体冻干特性.结果表明:冻干收缩率随着失水程度增加而增大,在失去约50%水分之后,干燥收缩停止;预冻温度越低,冻干收缩率越小.采取合理的冻干工艺对干燥收缩率进行控制,保证陶瓷铸型结构的完整性,快速铸出涡轮叶片,验证了新工艺的可行性和有效性.更多还原

【Abstract】 In this paper,a novel indirect solid freeform fabrication process was developed by combining gelcasting with stereolithography(SL) technique to manufacture integral ceramic casting molds for hollow turbine blades with converging-expanding film cooling holes.Based on the model of hindered drying shrinkage,a calculation formula of critical drying shrinkage was derived.Through experimental research,freeze-drying characteristics of gelcasting green bodies were discovered.The freeze-drying shrinkage was increased with water lose degree.After losing about 50 percent of water,the green body stopped shrinking.With the decrease of pre-freezing temperature,the freeze-drying shrinkage reduced.A suitable lyophilization process was adopted to control the freeze-drying shrinkage,and the structural integrity of ceramic casting mold was maintained.A rapid casting case study was presented to verify the feasibility and effectiveness of the proposed process.更多还原