3D打印氧化硅基陶瓷型芯的各向异性研究

Research on Anisotropy of 3D Printed Silicon Oxide-based Ceramic Cores

陶瓷型芯作为航空发动机叶片精密铸造的必需转接件,传统制造工艺越来越难以满足其对性能的要求。目前,3D打印技术因其具有成型零件精度高、生产成本低、综合性能良好等优势,能够在一定程度上解决传统制造工艺面临的问题,尤其是在陶瓷型芯的制造中具有很大的潜力。通过使用DLP光固化3D打印技术以及高温烧结制备了陶瓷芯型试样,研究了不同打印方向对氧化硅基陶瓷型芯试样的微观组织与性能的影响。结果表明:横向与竖向打印的陶瓷型芯经烧结后,打印方向对陶瓷型芯的气孔率没有明显的影响;铺料层所在平面组织均匀,铺料层之间具有明显的结合缝隙;在垂直于铺料层的方向上线收缩最为明显,最大线收缩为2.21%;横向打印的陶瓷型芯的抗弯强度是竖向打印的2倍;当温度由室温升至203℃阶段时,陶瓷型芯试样发生急剧膨胀,且竖向打印试样热膨胀系数明显大于横向的;当温度超过203℃,两种打印方向的陶瓷芯型的热膨胀系数相差较小。

Ceramic cores are necessary adapters for precision cast of aero engine blades,and it is increasingly difficult for traditional manufacturing processes to meet their performance requirements.At present,3D printing technology can solve these problems that the traditional manufacturing processes face to some extent because of its advantages such as high precision of molded parts,low production cost,and good comprehensive performance.There is great potential in the manufacture of ceramic cores especially.In this paper,the ceramic core specimens were prepared by using a DLP light curing 3D printing technology followed by a high temperature sintering.The effects of different printing directions on the microstructures and properties of silicon oxide-based ceramic core specimens were investigated.The results show that the printing direction has no significant effect on the porosity of as-sintered ceramic cores specimens prepared by horizontal and vertical printing.The microstructures of specimens in the powder-spread layer are uniform,and there are obvious bonding gaps between the powder-spread layers.The linear shrinkage is most obvious in the direction perpendicular to the powder-spread layer,and maximum linear shrinkage is 2.21%.The The flexural strength of horizontally printed specimen is more than twice that of vertically printed specimen.When the temperature rises from room temperature to 203℃,the ceramic core specimens inflate rapidly.The thermal expansion of vertically printed specmen is greater than that of horizontally printed specimen.After the temperature exceeds 203℃,the thermal expansions of both specimens are almost identical.