Strength of Polycrystalline Ceramics under Shock Compression

Shock loading on AlN ceramics: A large scale molecular dynamics study

The nanoscale structure of shock waves in high strength AlN ceramics is studied using molecular-dynamics simulations. Impacts using four independent crystallographic directions, with particle velocities in the range 0.8–4.0 km/s, reveal the generation of a welldefined two-wave structure, consisting of an elastic precursor followed by a wurtzite-torocksalt structural transformation wave (STW). I...

Fracture of Ceramics with Near Surface Gradient Residual Stresses

The fracture toughness and strength of ceramics can be improved with respect to monolithic ceramics by developing graded materials as laminates composed of periodic alternating layers of one material separated by layers of a second material. The second layer must contain residual compressive stresses which are induced during densification because of differential thermal contraction of the layer...

Creep of Polycrystalline Magnesium Aluminate Spinel Studied by an SPS Apparatus

A spark plasma sintering (SPS) apparatus was used for the first time as an analytical testing tool for studying creep in ceramics at elevated temperatures. Compression creep experiments on a fine-grained (250 nm) polycrystalline magnesium aluminate spinel were successfully performed in the 1100-1200 °C temperature range, under an applied stress of 120-200 MPa. It was found that the stress expon...

Shock compression and release of polycrystalline magnesium oxide

Dynamic compressive behaviour of ceramics under lateral confinement

A new experimental technique for imposing lateral confinement on specimens subjected to high-strain-rate uniaxial compression is being developed. A brief description of the experimental technique, as well as some preliminary experimental results of the technique are presented in this paper. The results show that under lateral confinement, the impact strength of a brittle glass ceramic increases...