Özet
Tailoring the SiC fiber-matrix interface in micron-sized fibers is crucial to attaining enhanced mechanical properties in ceramic reinforced composites. Herein, the authors report the growth of boron nitride nanotubes (BNNT) onto SiC fibers (SiCf), creating a fuzzy fiber architecture to promote the surface area for a defined load path of fiber to the matrix and improve the mechanical properties of these structures. Successful BNNT-growth is achieved by a boron oxide chemical vapor deposition method combined with growth vapor trapping with optimum parameters of 1200 °C and 1 h, comparatively low temperature to those reported in the literature. The strength loss of SiCf after exposure to 1200 °C was attributed to high process temperature, similar to what has been observed in the literature. Hence, BNNT growth does not lead to additional strength loss on these fibers measured by a single fiber tensile test. Moreover, through this direct growth method, grown BNNTs utilize a surface-anchored BNNTs/SiCf, creating a good matrix adhesion to prevent fiber-fiber sliding and pullout and increasing the interfacial shear strength (IFSS) with epoxy. Furthermore, microbond tests show that fuzzy BNNTs/SiCf architecture increased IFSS by at least 87.8% compared to as-received SiCf.
| Orijinal dil | İngilizce |
|---|---|
| Makale numarası | 109033 |
| Dergi | Composites Science and Technology |
| Hacim | 216 |
| DOI'lar | |
| Yayın durumu | Yayınlandı - 10 Kas 2021 |
Bibliyografik not
Publisher Copyright:© 2021
Finansman
The IFSS was calculated with Equation (4), and the embedded fiber length (le), fiber diameter (df), and the microdroplet length were measured using an optical microscope, respectively, and Fmax is the maximum load. Results were represented either as the average value of calculated IFSS’ or as the slope of the regression line intercepting origin over the force–embedded area plot. Since the measured forces were considerably lower than load cell capacity, the maximum loads obtained from UTM were corrected according to a calibration process explained in detail in supporting information.Tensile test results for as-received, desized, and BNNTs/SiCf were summarized in Table 1. Since BNNTs growth in the GVT-BOCVD system is a high-temperature process, the SiCf was exposed to various gases at temperatures between 1000 °C and 1200 °C and studied to explore the effect of reactant and temperature concerning the overall mechanical properties of these fibers. The average tensile strength of desized SiCf (with DMF) was similar to as-received SiCf, with 2295 ± 36 MPa for desized compared to 2101 ± 98 MPa for the as-received SiCf, which was in line with reported values by the supplier [42]. To identify the most significant strength loss due to BNNT growth by GVT-BOCVD system, a heat treatment at 1200 °C, the highest recognized temperature during a growth process, was studied, and the strength of SiCf decreased to 1833 ± 87 MPa. This strength loss was observed to be more severe under an ammonia atmosphere, with the tensile strength of the SiCf dropping to 1088 ± 59 MPa. However, the fuzzy BNNTs/SiCf (sample code T-5 in Table 1) showed no further strength loss (926 ± 46 MPa) than T-4. Furthermore, studies on the literature where BN coating was applied to the surface of the SiC fibers also show a similar decrease in the tensile strength of the fibers, further supporting the non-effect of the BNNT growth on the fiber surface [43,44]. Moreover, BNNT/SiCf showed a high Weibull modulus indicating a uniform distribution of flaws along with the fiber and little variation in the tensile strength (Fig. 4 (b)). All sample codes were given in detail in Table 1.The authors would like to acknowledge the Safran Herakles for funding this project. The authors would like to thank the National Research Center on Membrane Technologies and ITU Universal Textile Design Center for their support. The authors would also like to thank Melike Mercan Yıldızhan and Deniz Ürk for their help in this research. The authors would like to acknowledge the Safran Herakles for funding this project. The authors would like to thank the National Research Center on Membrane Technologies and ITU Universal Textile Design Center for their support. The authors would also like to thank Melike Mercan Yıldızhan and Deniz Ürk for their help in this research.
| Finansörler | Finansör numarası |
|---|---|
| ITU Universal Textile Design Center | |
| National Research Center on Membrane Technologies | |
| Safran Herakles | |
| Universiti Teknologi Malaysia | 43,44 |