Support-Free Infiltration of Selective Laser Sintered (SLS) Non-Metallic Preforms

该项目的研究目标是了解使用选择性激光烧结（一种自由成形制造技术）生产的渗透非金属零件中缺陷的起源。这些部件缺陷包括渗透剂的不完全填充和局部渗透剂在表面不规则处过度挤出到部件表面上。 这一办法有三个方面。 首先，润湿理论将扩展到这个问题，并为缺陷起源建立基础。 其次，在这一科学进步的指导下，将创建一种工艺来去除和/或减轻以前在硅渗透碳化硅部件中观察到的缺陷。 最后，将通过将这些科学评估结果应用于不同的促进缺陷形成的零件几何形状以及不同的材料系统（包括钴渗透碳化钨和环氧渗透石墨）来验证这些结果。如果成功，这些研究结果将有助于开发和成熟一种新的制造路线，以制造具有复杂几何形状和出色表面光洁度的低成本非金属零件。 包括商业上重要的难以加工的材料，如钴-碳化钨，硅-碳化硅和石墨-石墨。 这将加强国内制造业的基础设施，使国内制造业能够更有效地在世界市场上竞争。

The research objective of this project is to learn the origin of defects in infiltrated non-metallic parts produced using Selective Laser Sintering, a freeform fabrication technique. These part defects include incomplete filling by the infiltrant and localized infiltrant over-extrusion onto the surface of the part at surface irregularities. The approach is threefold. First, wetting theory will be extended to this problem and will establish a basis for defect origin. Second, guided by this scientific advance, a process will be created to remove and/or mitigate defects observed previously in silicon infiltrated silicon carbide parts. Last, the results of this scientific assessment will be verified by applying them to different part geometries that promote defect formation and to different materials systems including cobalt infiltrated tungsten carbide and epoxy infiltrated graphite.If successful, these research results will enable development and maturing of a new manufacturing route for creating low-cost non-metallic parts with complex geometry and excellent surface finish. Included are commercially important hard-to-process materials such as cobalt-tungsten carbide, silicon-silicon carbide and graphite-graphite. This will strengthen the domestic manufacturing infrastructure and enable domestic manufacturing to compete more effectively in the world market.