The mechanics of matrix cracking in brittle-matrix fiber composites

Enhanced toughness and stable crack propagation in a novel tungsten fibre-reinforced tungsten composite produced by chemical vapour infiltration

“…For the evaluation, the actual crack length must be known. In an inhomogeneous composite material such as W f /W the determination of this length using only a surface observation is not possible [26]. Without detailed knowledge on the crack length over the whole sample thickness, the initial crack length, i.e.…”

Loading configuration effects on the strength reliability of alumina–zirconia multilayered ceramics

“…This broad range of strength values and their inherent brittleness have limited the use of ceramics in structural applications. However, as a direct consequence of remarkable progress in terms of microstructural design and advanced processing [1][2][3] , toughness and reliability of structural ceramics have been increasingly enhanced by recourse to crack shielding resulting from microstructure -related mechanisms [4][5][6][7][8][9][10][11].…”

Fatigue crack propagation in aluminum- lithium alloy 2090: Part I. long crack behavior

“…Finally, the fatigue behavior of aluminum-lithium alloys provides a prime example of "extrinsic tougheningll, where superior 13 crack growth propert i es are ach i eved through mi c:ostructura 1, mechanical or environmental mechanisms which impede crack advance by locally reducing the "crack driving force", rather than by increasing the mi crostructura 1 crack growth res i stance (19,20). A 1 though commonly employed to toughen brittle materials, e.g., by utilizing the transformation, microcrack or ligament toughening mechanisms in ceramics (19,21,39), the crack tip shielding approach is generally less applicable in metallic materials due to their high intrinsic toughnes s. The exception to th i sis where crack extens i on proceeds at low applied "driving forces", e.g., during sub-critical crack growth, where the effect can be extremely potent. However, it is important to note that the origins of shielding generally involve mechanisms that operate primarily behind the crack tip, rather than in the frontal zone.…”