Fibre-Matrix Interface Development during High Temperature Exposition of Long Fibre Reinforced SiOC Matrix

2013 ◽  
Vol 592-593 ◽  
pp. 401-404
Author(s):  
Zdeněk Chlup ◽  
Martin Černý ◽  
Adam Strachota ◽  
Martina Halasova ◽  
Ivo Dlouhý

The fracture behaviour of long fibre reinforced composites is predetermined mainly by properties of fibre-matrix interface. The matrix prepared by pyrolysis of polysiloxane resin possesses ability to resist high temperatures without significant damage under oxidising atmosphere. The application is therefore limited by fibres and possible changes in the fibre matrix interface. The study of development of interface during high temperature exposition is the main aim of this contribution. Application of various techniques as FIB, GIS, TEM, XRD allowed to monitor microstructural changes in the interface of selected places without additional damage caused by preparation. Additionally, it was possible to obtain information about damage, the crack formation, caused by the heat treatment from the fracture mechanics point of view.

2011 ◽  
Vol 465 ◽  
pp. 455-458 ◽  
Author(s):  
Zdeněk Chlup ◽  
Martin Černý ◽  
Adam Strachota ◽  
Ivo Dlouhý

Fracture response of matrix prepared by pyrolysis of polysiloxane resin used for composite reinforced by long fibres was the main goal of this contribution. A set of composites with matrix prepared by partial pyrolysis of polysiloxane resin was studied. An effect of pyrolysis temperature on the composite behaviour and fracture resistance was monitored. An optimal procedure of pyrolysis was established. Heat treatment at 1550°C in air atmosphere was conducted on fully pyrolysed matrix to explore its high temperature potential. Determination of reliable parameters characterising microstructural changes in the matrix by instrumented indentation technique was used. Both optical and scanning electron microscopy was employed in microstructural observations and fracture mechanism qualification. Observation of indents and associated cracking caused by microstructural changes as well as 3D surface reconstruction using confocal microscopy was employed.


2018 ◽  
Vol 774 ◽  
pp. 644-649
Author(s):  
M.L. Velasco ◽  
Federico París ◽  
E. Correa

This paper deals with the study of the actual progression of the damage in the 90 degrees lamina of a composite. It has been proved and observed that isolated debondings between fibres and matrix are the first manifestation of damage in the weakest lamina, the 90 degrees lamina in a [0,90]S laminate. It was also numerically supported that this first phase was independent of the thickness of the 90 degrees lamina, not being then affected by the “scale effect”. The continuation of this first phase of damage is the objective of the present paper. To this end, a multiscale model is created involving the debonding between fibre and matrix and studying the kink of this crack, abandoning the fibre-matrix interface and entering into the matrix to produce a meso-transverse crack in the 90 degrees ply. The study is based on the application of Fracture Mechanics to an incipient kinked crack that starts from a debonding between fibre and matrix. It is concluded that this second phase of damage, playing with the thickness of the 90 degrees lamina, is not affected by the scale effect, as the variation of the energy release rate of the kinked crack is not significantly influenced by the variation of the thickness of the lamina.


1990 ◽  
Vol 194 ◽  
Author(s):  
L. Xiao ◽  
Y. S. Kim ◽  
Reza Abbaschian

AbstractChemical compatibility between oxide coated Nb filament reinforcements and MoSi2 was investigated. It was determined that ZrO2, Al2O3, and mullite coatings were chemically compatible with both Nb and MoSi2. Comparison between coated and uncoated filaments indicated that the coatings reduced the thickness of the interaction zone. The fracture toughness of the Nb filament reinforced composites showed an increase, while W filament reinforced composite showed a decrease, in the toughness compared to that of the matrix. The results are discussed in terms of the mismatches in the coefficients of thermal expansion and the bonding characteristics of the reinforcement/matrix interface.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hanna M. Brodowsky ◽  
Anne Hennig

Abstract Natural fibre–reinforced composites are more sustainable than other composites with respect to the raw materials. Their properties are attractive due to high specific properties, and especially so wherever high damping is valued. As the interphase between fibre and matrix is the region of highest stresses, a strong bond between fibre and matrix is essential for any composites’ properties. The present study compares two methods of determining the interfacial shear stress in natural fibre–reinforced composites: the single fibre fragmentation test and the single fibre pullout test. The studied composites are flax fibre reinforced epoxy. For a variety of fibre–matrix interaction, the fibres are treated with a laccase enzyme and dopamine, which is known to improve the fibre–matrix shear strength. In the observed samples, single fibre fragmentation test data, i.e. of fracture mode and fragment length, scatter when compared to pullout data. In single fibre pullout tests, the local interfacial shear strength showed a 30% increase in the laccase-treated samples, compared to the control samples. The method also permitted an evaluation of the frictional stress occurring after surface failure.


Author(s):  
N. Selva Kumar ◽  
T. M. Sakthi Muruga ◽  
S. Ganapathy ◽  
K. Arulkumar

Our Experimentation finds, reaction of fibre external analysis on tensile, flexural and chemical resistance properties were studied for sisal fibre reinforced composites. Fibre surface analysis has done to produce link between fibre and the matrix to improve the mechanical properties. Fibre surface analysis were done by boiled the sisal fibres in different % of NaOH and treated the fibres in different % of NaOH, treated in acetic acid and methanol. Polyester resin have used as the matrix for preparing the composites and these properties for Natural sisal fibre reinforced composites were also studied. From the results it was observed that 25% NaOH boiled sisal fibre reinforced composites have higher tensile, flexural properties than other composites. Natural sisal fibre composites show fewer properties than treated composites. Chemical inertness properties indicate that all sisal fibre reinforced composites are resistance to all chemical agents except carbon tetra chloride.


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