Matrix Concepts and Processing Protocols for Robust SiC-Based CMCs
Abstract
A research program is proposed to address the Navy~s need for new manufacturing processes foraffordable non-oxide fiber-reinforced ceramic matrix composites (CMCs) for use in hot sectioncomponents of future sea-based propulsion systems. One of the principal objectives is toestablish the underlying science-base needed for design of new matrices and protocols for theirsynthesis. The concept of interest involves two processing steps: (i) creation of a porous matrixcomprising both SiC and (reactive) C, either by polymer impregnation and pyrolysis or throughparticulate slurry infiltration routes; and (ii) melt infiltration of Si alloys containing rare earthmetals (notably Y) which, upon reaction with C, form a combination of SiC and a high meltingpoint silicide (e.g. YSi). Control of the size scales of the pore structures and the spatialdistribution of the constituents of the porous matrix is crucial, to ensure complete infiltration andreaction of the molten alloy, without significant remnant porosity. Understanding of porestructures will be gleaned from x-ray computed tomography imaging of representative porousnetworks coupled with theories of fluid flow and thermal decomposition of precursors. One keychallenge will be to devise strategies that enable complete filling of pore regions of highlydisparate size scales. One promising approach involves use of particles with multi-modal sizedistributions, designed to optimally fill void spaces within and between tows.The knowledge gained from this research would be transitioned on a frequent and timely basis tocollaborators at Pratt & Whitney, where a complementary industrial research activity is inprogress. The program will build on previous ONR-sponsored work and associated facilities atUCSB that enable the fundamental study of CMC synthesis by reactive alloy melt infiltration,slurry impregnation and polymer infiltration and pyrolysis, including a new facility for in-situ xraycomputed tomography of the pyrolysis process developed under the previous program inclose collaboration with the Advanced Light Source at LBNL. The expected benefit to the USNavy is an augmented processing science base that would enable the development of moreaffordable CMCs with improved performance and durability. Broader benefits include anenhanced scientific foundation for high temperature materials and contributions to the trainingand diversity of human resources in this important area.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712276
Entities
People
- Frank W. Zok
Organizations
- Office of Naval Research
- United States Navy
- University of California