Effect of mixed mode I/II on fracture behaviour of laminated metal matrix composites

Abstract

The effects of mixed mode loading (I/II) on the fracture toughness and fracture behaviour of both 6090/SiC/20p-6013 diffusion bonded laminates and 2080/SiC/20p-2080 adhesive bonded laminates tested in the crack arrester orientation were investigated. The effects of layer thickness and volume fraction ratio on the fracture behaviour under the mixed mode were also studied. The fracture behaviour under mode I/II of available similar discontinuously reinforced aluminium (DRA) materials was additionally compared to that of the laminates. The fracture behaviour of laminates under mode I/II was dependent on the volume fraction ratio and generally different from that of the monolithic and DRA. The increase in the fracture toughness of DRA by lamination with ductile layers under mode I changes somewhat under increasing load mixity, for 75/25 and 50/50 diffusion bonded laminate and 60/40 adhesive bonded laminate ABL. This results from extensive interfacial separation and delamination between the layers.

Layer-Graded Cu/B4C/Graphite Hybrid Composites: Processing, Characterization, and Evaluation of Their Mechanical and Wear Behavior

“…Hence, it can be proposed that delamination and crack tip blunting are the principal components in improving the crack growth resistance of the LGCs. Hassan (32) has also showed similar crack deflection and improved fracture toughness in two-layer Al composites (2080/ 20%SiC p )/Al alloy (2080). Zechnera and Kolednik (33) showed that the introduction of a soft polymer layer in Al multilayer composites significantly improved the crack growth resistance.…”

The effect of mixed mode I/II on the fracture toughness and fracture behavior of nano-structured metal matrix composites

“…The conventional Al/SiC p systems shown in Fig. 6 [2,23,26] exhibit little effects of mode mixity on the normalized total fracture energy, although the damage mechanisms in such composites are quite different than that exhibited presently, as discussed below.…”

“…In conventional Al/SiC p composites, damage typically takes the form of fractured SiC p particulates and/or SiC p /matrix interface decohesion [2,23,[26][27][28][29][30][31]. Fracture nucleation in such systems appears to depend on the normal/hydrostatic stress and damage evolves during tensile straining until catastrophic failure occurs via void link up through the matrix [28][29][30][31].…”

“…While the void nucleation mechanisms in such systems have not been systematically studied to date, the interesting effects of mode 6. G total /G IC (G total /G IQ ) versus loading angle for mixed mode I/II tests on notched and fatigue pre-cracked samples tested at room temperature and 498 K. Behavior of some conventional metal matrix composites from previous work [2,23,26] is also provided. mixity suggest that certain levels of mode mixity appear to delay void nucleation in these materials, thereby producing a higher toughness at both 298 K and 498 K in both fatigue pre-cracked and notched conditions.…”

“…Mixed mode tests were performed using the method described by Suresh et al [19] Jen et al [21] and Hassan [23] on both notched and fatigue pre-cracked samples. The stress intensities K IQ and K IIQ were calculated as follows [21]:…”