Residual stress and interface debonding behavior in Si3N4w reinforced SiCN composites prepared by the PIP process: A case study

Polymer infiltration and pyrolysis (PIP), as a preparation route for ceramic matrix composites, employs the polymer-to-ceramic transformation inside the preforms to gradually buildup the matrix. The effects of the structural transformation on the residual stress and on the interface debonding behavior of PIP derived Si3N4 whisker reinforced SiCN (Si(3)N(4)w/SiCN) composites are analyzed. Accordingly, the Si(3)N(4)w whisker in the composites are under residual compressive stress after the formation of the polymer-derived ceramic matrix. An increase in the pyrolysis heating rate from 1 to 10degree celsius/min effectively lowers the residual stress from 195.8 to 91.3 MPa. Interface fracture energies of Si(3)N(4)w/SiCN derived from the debonding behavior significantly rise from <11.91 to 21.82 J/m(2) with the annealing temperature from 900 to 1400degree celsius. The residual stress and interfacial behavior are related to the in-situ densification/shrinkage and structural rearrangement during pyrolysis and annealing.

Automated summary

Polymer infiltration and pyrolysis is an effective method for preparing ceramic matrix composites. The transformation of polymer to ceramic during the process affects the residual stress and interface behavior in the composites.