Partially stabilized zirconia moulds fabricated by stereolithographic additive manufacturing via digital light processing

摘要

Partially stabilized zirconia (PSZ) moulds for aluminium casting were fabricated by stereolithographic additive manufacturing via digital light processing (DLP). Green parts were fabricated on DLP equipment using curable ceramic suspension. These suspensions were studied by performing photopolymerisable and rheological characterisations. Thermogravimetry (TGA) was used to analyse thermal stability of the suspension. Phase composition of sintered parts was determined by X-ray diffraction (XRD), while mechanical properties of green and sintered parts were studied by three-point bending testing. Flexural strength and Young's modulus of sintered parts were determined to be 803.7 +/- 59 MPa and 203.4 +/- 17 GPa, and these values decreased to 41.5 +/- 3.9 MPa and 3.1 +/- 0.3 GPa for green parts, respectively. Large pores were suggested to originate failure, with fracture mode being predominantly intergranular. Finally, sintered ceramic investment moulds were prepared by stereolithography and subsequently used for aluminium casting purposes. Dimensions of green parts before sintering were about 0.5% smaller than design values within the plane of layers, and approximately 0.5% larger than design values perpendicular to the layers. Sintering shrinkage was around 22% in both directions. Surface roughness of sintered moulds and aluminium casting materials were quantitatively determined by profilometry.