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

本项目的研究目的是了解使用自由成形技术——选择性激光烧结（Selective Laser Sintering）生产的渗透非金属零件的缺陷来源。这些零件缺陷包括浸渍剂不完全填充和局部浸渍剂在表面不规则处过度挤压到零件表面。这种方法有三个方面。首先，将润湿理论推广到这一问题，为缺陷的起源建立基础。其次，在这一科学进步的指导下，将创建一种工艺来消除和/或减轻先前在硅渗透碳化硅部件中观察到的缺陷。最后，将科学评估的结果应用于促进缺陷形成的不同零件几何形状和不同的材料系统，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，这些研究成果将使开发和成熟新的制造路线，以创造具有复杂几何形状和良好表面光洁度的低成本非金属零件。其中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基础设施，使国内制造业能够在世界市场上更有效地竞争。

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.