Issue 62

Y. S. Rao et alii, Frattura ed Integrità Strutturale, 62 (2022) 240-260; DOI: 10.3221/IGF-ESIS.62.17

deteriorates effective load transfer from the matrix to the reinforcement. As a result, the carbon fiber-epoxy interface bond is disrupted at a few locations as shown in Fig. 6(b-c).

Figure 5: Mode-I type toughness test specimen fractured surface morphology: (a-c) neat CFREC, (d-f) 6MoS 2 -CFREC and (g-i) 6BN CFREC.

Figure 6: Mode-I type toughness test specimen fractured surface morphology: (a-c) 8BN-CFREC.

Mixed-mode I/II fracture toughness The force versus displacement behavior of mixed-mode I/II test is represented in Fig. 7(a-b). The stiffness and peak load increased with an increase of hBN filler content up to 6 wt.% and found it is highest in hBN filler loaded CFREC as shown in Fig. 7(a). This is attributed to higher stiffness of hBN filler compared to MoS 2 . The increasing trend of stiffness and peak load also observed due to the addition of MoS 2 filler loading. However, the maximum stiffness and peak load were obtained at 4 wt.% MoS 2 filler loading and beyond 4 wt.% gradually reduce the stiffness and peak load of the composites as shown in Fig. 7(b). This is attributed to low coefficient of friction of MoS 2 layered stacking sheets that slips easily in the matrix and reduced the stiffness. It is found that a significant difference in peak load and stiffness between 4 and 6 wt.% hBN filler

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