研究了用于Freeze-form Extrusion Fabrication工艺的水基ZrB2膏体的挤出流变性能。动态力学分析表明该膏体可以作为粘弹塑性体来处理:在挤出过程中,屈服前表现为粘弹性固体特性,屈服后表现为粘塑性流体特性。虽然有剪切变稀现象,但在实际的挤出工艺范围内表观粘度变化平稳,水基ZrB2膏体可稳定挤出,并可用宾汉体流体进行描述。挤出实验表明:挤出速度高于0.1mm/s时不发生液相迁移现象,可以用Benbow—Bridgwater模型来预测挤出压力和挤出参数的关系。
The rheological behavior during extrusion of aqueous ZrB2 paste for Freeze-form Extrusion Fabrication process was investigated in this paper. The dynamic mechanical analysis shows that the paste can be treated as visco-elastoplastic material. The paste shows the characteristic of viscoelastical solid during the pre-yield stage and viscoplastic fluid during the post-yield stage. Although the paste has shear-thirming property, the apparent viscosity is rel-atively steady in the actual extrusion flow rate range, so the paste can be steadily extruded and can be described as Bingham fluid. The extrusion experimentations show that: the liquid phase migration phenomena will appear when the extrusion velocity is higher than 0.1 ram/s, and the relation between of extrusion pressure and extrusion parameters can be predicted by Benbow-Bridgwater model.