Scatter of Fracture Toughness befor and after Stable Crack Extension

Fracture toughness and fatigue crack growth characteristics of nanotwinned copper

Recent studies have shown that nanotwinned copper (NT Cu) exhibits a combination of high strength and moderate ductility. However, most engineering and structural applications would also require materials to have superior fracture toughness and prolonged subcritical fatigue crack growth life. The current study investigates the effect of twin density on the crack initiation toughness and stable ...

Fracture Toughness of Wood and Wood Composites during Crack Propagation

The mode I fracture toughness as a function of crack length of medium density fiberboard (MDF), particle board (PB), and Douglas-fir (DF) were all measured using a new energy-based method. PB and MDF are examples of composites that develop fiber bridging during crack propagation, which causes their toughness to increase with crack length. Longitudinal cracks in DF also displayed fiber bridging ...

Buoyancy-driven crack propagation: the limit of large fracture toughness

Fracture toughness of graphene.

Perfect graphene is believed to be the strongest material. However, the useful strength of large-area graphene with engineering relevance is usually determined by its fracture toughness, rather than the intrinsic strength that governs a uniform breaking of atomic bonds in perfect graphene. To date, the fracture toughness of graphene has not been measured. Here we report an in situ tensile testi...

Mode I Fracture Toughness of a Small-Grained Silicon Nitride: Orientation, Temperature, and Crack Length Effects

The Mode I fracture toughness (KIC) of a small-grained Si3N4 was determined as a function of hot-pressing orientation, temperature, testing atmosphere, and crack length using the single-edge precracked beam method. The diameter of the Si3N4 grains was <0.4 μm, with aspect ratios of 2–8. KIC at 25°C was 6.6 ± 0.2 and 5.9 ± 0.1 MPa?m1/2 for the T–S and T–L orientations, respectively. This differe...