Support-Free Infiltration of Selective Laser Sintered (SLS) Silicon Carbide Preforms

Non-metallic objects are often difficult to manufacture due to high melting temperatures, poor sinterability, limited ductility, and difficulty in machining. Freeform fabrication techniques coupled with liquid infiltration offer a cost-effective and rapid manufacturing mechanism for composite parts with complex geometry and adequate properties. Selective laser sintered (SLS) silicon carbide (SiC) preforms infiltrated with liquid silicon develop localized infiltrant overextrusions onto surfaces and at surface irregularities. Several shrinkage mechanisms including densification were studied as possible causes of these overfilling extrusions, and the results are discussed below. This research was supported by NSF Grant Number DMI-0522176.