X-ray computed tomography of microstructure evolution during matrix impregnation and curing in unidirectional fiber beds

Abstract Microstructural evolution during axial impregnation and subsequent curing of a preceramic polymer in unidirectional ceramic fiber beds is studied using X-ray computed tomography. The principal goal is to identify connections between void locations, void sizes, local fiber bed porosity, fiber movement, and impregnation conditions. The degree of saturation after impregnation is found to increase with instantaneous capillary number. But, because of the need to create pathways for gas escape during curing, fiber beds with high saturation after impregnation show the largest reductions in saturation during curing. Notwithstanding, saturation after curing increases with instantaneous capillary number. Voids tend to form in the largest channels between fibers, where the local fiber bed porosity is high, during both impregnation and curing. Void formation is typically accompanied by fiber movement that increases both the local fiber bed porosity near voids and the overall non-uniformity in the fiber bed, as measured by local porosity entropy.

[1]  David L. Poerschke,et al.  Intermediate Temperature Internal Oxidation of a SiC/SiCN Composite with a Polymer-Derived Matrix , 2016 .

[2]  Frank W. Zok,et al.  In-situ 3D visualization of composite microstructure during polymer-to-ceramic conversion , 2018 .

[3]  A. Kohyama,et al.  Effect of SiC particle dispersion on microstructure and mechanical properties of polymer-derived SiC/SiC composite , 2003 .

[4]  Véronique Michaud,et al.  A Review of Non-saturated Resin Flow in Liquid Composite Moulding processes , 2016, Transport in Porous Media.

[5]  R. Naslain.  Design, preparation and properties of non-oxide CMCs for application in engines and nuclear reactors: an overview , 2004 .

[6]  L. Michel,et al.  Coupled visco-mechanical and diffusion void growth modelling during composite curing , 2010 .

[7]  V. Michaud,et al.  Permeability and capillary effects in a channel-wise non-crimp fabric , 2018 .

[8]  Nitin P. Padture,et al.  Advanced structural ceramics in aerospace propulsion. , 2016, Nature materials.

[9]  C. Binetruy,et al.  Unloading during the infusion process: Direct measurement of the dual-scale fibrous microstructure evolution with X-ray computed tomography , 2018, Composites Part A: Applied Science and Manufacturing.

[10]  A. Long,et al.  Uncertainty in the manufacturing of fibrous thermosetting composites: A review , 2014 .

[11]  Chung Hae Park,et al.  Modeling void formation and unsaturated flow in liquid composite molding processes: a survey and review , 2011 .

[12]  Frank W. Zok,et al.  Insights from in-situ X-ray computed tomography during axial impregnation of unidirectional fiber beds , 2018 .

[13]  Alberto Ortona,et al.  Manufacturing SiC‐Fiber‐Reinforced SiC Matrix Composites by Improved CVI/Slurry Infiltration/Polymer Impregnation and Pyrolysis , 2004 .

[14]  G. Springer,et al.  Curing of Epoxy Matrix Composites , 1983 .

[15]  V. Michaud,et al.  Stress-initiated void formation during cure of a three-dimensionally constrained thermoset resin , 2001 .

[16]  Francesco De Carlo,et al.  TomoPy: a framework for the analysis of synchrotron tomographic data , 2014, Journal of synchrotron radiation.

[17]  R. Ritchie,et al.  Real-time Quantitative Imaging of Failure Events in Materials under Load at Temperatures above 1,600 , 2012 .

[18]  Rikard Gebart,et al.  Influence from process parameters on void formation in resin transfer molding , 1994 .

[19]  Edu Ruiz,et al.  Porosity reduction using optimized flow velocity in Resin Transfer Molding , 2008 .

[20]  Local entropy characterization of correlated random microstructures , 1996, cond-mat/9611015.

[21]  R. Riedel,et al.  Pressureless fabrication of dense monolithic SiC ceramics from a polycarbosilane , 2014 .

[22]  Frank W. Zok,et al.  Ceramic-matrix composites enable revolutionary gains in turbine engine efficiency , 2016 .

[23]  Y. Wielhorski,et al.  Theoretical Approach of Bubble Entrapment Through Interconnected Pores: Supplying Principle , 2012, Transport in Porous Media.

[24]  G. Requena,et al.  An in situ investigation of microscopic infusion and void transport during vacuum-assisted infiltration by means of X-ray computed tomography , 2015 .

[25]  Paolo Colombo,et al.  Polymer‐Derived Ceramics: 40 Years of Research and Innovation in Advanced Ceramics , 2010 .

[26]  David L. Poerschke,et al.  Crystallization behavior of polymer-derived Si-O-C for ceramic matrix composite processing , 2018 .

[27]  A. Kohyama,et al.  Development of SiC/SiC composites by PIP in combination with RS , 2001 .

[28]  A. Kohyama,et al.  Consolidation of polymer-derived SiC matrix composites: processing and microstructure , 2002 .

[29]  F. Sket,et al.  Effect of curing cycle on void distribution and interlaminar shear strength in polymer-matrix composites , 2011 .

[30]  J. L. Kardos,et al.  Void growth and resin transport during processing of thermosetting — Matrix composites , 1986 .