A high temperature cured self-healing epoxy is demonstrated by incorporating microcapsules of poly (dimethylsiloxane) (PDMS) resin and separate microcapsules containing an organotin catalyst. Healing is triggered by crack propagation through the embedded microcapsules in the epoxy matrix, which releases the healing agents into the crack plane initiating crosslinking reactions. A series of taper...

Bones are the principal structural components of a skeleton; they play unique roles in the body providing its shape maintenance, protection of internal organs and transmission of forces. Ultimately, their structural integrity is vital for the quality of life. Unfortunately, bones can only sustain loads until a certain limit, beyond which they fail. Understanding a fracture behaviour of bone is ...

The orientation dependence of Charpy toughness has been investigated in API-X80 linepipe steel. The occurrence of delamination and preferential alignment of {100} cleavage planes are found to contribute to the observed anisotropy in Charpy properties. Delamination is also related to the presence of banding in the hot–rolled alloy, and the additional plasticity it entails during the process of f...

Relations between fracture toughness and microstructural details have been calculated for ductile materials based on a dilatational plasticity constitutive model that has recently been proposed. The model generalizes the Gurson model to account for both void growth and coalescence with explicit dependence on void shape and distribution effects. Based on a small scale yielding formulation of cra...

Low fracture toughness of ferroelectric ceramics calls for a reliability concern in the development of smart structures. For ferroelectrics under mechanical and electrical loadings, the intensified stress and electric fields in the vicinity of a crack-like flaw lead to domain reorientation. The switched domains induce incompatible strain near the flaw and consequently change the apparent fractu...

Systematic changes in composition were employed to increase the notch toughness of a variety of Fe-based Bulk Metallic Glasses (BMGs). The Fe50Mn10Mo14Cr4C16B6 BMG possessed very high hardness (e.g. 12GPa) but very low notch toughness (e.g. 5.7MPam) at room temperature, consistent with fracture surface observations of brittle features. Many of the other Fe-BMG variants, created to change the Po...

‘Curving’ could occur in Mode I brittle fracture and it can be attributed to the constraint. The variation of the apparent fracture toughness with constraint with or without crack curving is investigated. Using a critical opening or hoop stress as the fracture criterion, it is demonstrated that a fracture event can be quantified by two mechanics parameters, i.e. K and A3 for fracture without cu...

Composite materials are prone to delamination as they are weaker in the thickness direction. Carbon nanotubes (CNTs) are introduced as a multiscale reinforcement into the fiber reinforced polymer composites to suppress the delamination phenomenon. This review paper presents the detailed progress made by the scientific and research community to-date in improving the Mode I and Mode II interlamin...

In the present study, M2 high speed steels were fabricated by using electro-slag rapid remelting process. Carbide structure was analysed and the fracture toughness and hardness were also measured after austenitization treatment at 1190 and 1210C followed by tempering treatment at 535C for billets with various diameters from 16 to 60 mm. Electro-slag rapid remelting (ESRR) process is an advanced...

In this work the fracture toughness of epoxy resin has been improved through the addition of low loading of single part and hybrid nanofiller materials. Functionalised multi-walled carbon nanotubes (f-MWCNTs) was used as single filler, increased the critical strain energy release rate, GIC, by 57% compared to the neat epoxy, at only 0.1 wt% filler content. Importantly, no degradation in the ten...