Anisotropy Control and High-Temperature Strengthening of Silica Ceramic Cores Fabricated by 3D Printing

Investigation on 3D printing of silica ceramic cores is crucial to the development of aviation level in China, but the related problems are high-temperature softening and structural anisotropy. Silica ceramic cores were fabricated by DLP light curing 3D printing technology using fused silica powder as a raw material and mullite powder as a modifier. The results show that the ceramic cores have a layer-packed anisotropic structure. The addition of a small amount of mullite powder promotes the sintering densification of ceramic powder and diffusion binding between printing layers. As a result, the structural anisotropy of ceramic cores is relieved, and the flexural strength is enhanced and tended to isotropy. For ceramic cores with 3% mullite powder, the high-temperature flexural strengths in horizontal and vertical printing are up to 18.5 MPa and 16.3 MPa, respectively, which can satisfy the demands for hollow blade casting.