Over‐infiltration mechanisms in selective laser sintered Si/SiC preforms

Purpose The paper aims to evaluate mechanisms for silicon overfilling including volume expansion of silicon on solidification for composite silicon/silicon carbide (SiC) objects generated using post‐process infiltration of selective laser sintered (SLS) SiC preforms. Design/methodology/approach Overfilling was characterized through geometrical means and microscopy, and results were used for further study and discussion of overfilling mechanisms. Findings Silicon overfilling in silicon infiltrated SLS SiC parts is attributed primarily to its infiltrant silicon volume expansion on solidification. Si/SiC composites were found to be thermally stable with good material bonding. Research limitations/implications Silicon as an infiltrant is unusual as it expands on solidification, whereas most infiltrants contract. Overfilling during infiltration of SLS porous performs is therefore not considered to be prevalent. Originality/value This paper provides an examination of the value of silicon as an infiltrant material for SLS SiC preforms. Various mechanisms are presented for volume change during post‐process infiltration of indirect SLS non‐metallic performs.