Carbon-nylon hybrid fibers modified silica sol shell with enhanced flexural strength and heat transfer for investment casting

Abstract

The carbon-nylon hybrid fibers were employed to modify the silica sol shell for investment casting, and these shells were sintered in vacuum. An optimized mixing process was applied to improve the dispersion of hybrid fibers in slurry, then resulting in the excellent slurry uniformity. The modified shell fabricated by slurry with 4 g/L hybrid fiber displays a higher sintered strength of 5.46 MPa, which is derived from the increased crack propagation path and the dissipated more loading energy through interfacial debonding and friction of the remained carbon fiber pull-out. In addition, the permeabilities of silica sol shells are obviously improved due to the existence of holes in matrix resulted from the melting of nylon fibers during the sintering process. Also importantly, the hybrid fibers modified shell exhibit a good heat transfer efficiency, which is related to the formed heat transfer channels caused by the remained carbon fibers in sintered shell.