Widespread processes in nature and technology are governed by the dynamical transition whereby a material an initially solid-like state, whether soft or hard, then yields. Major unresolved questions concern any will yield smoothly gradually (``ductile'' behavior) fail abruptly catastrophically (``brittle'' behavior); roles of sample annealing, disorder, shear band formation onset yielding failu...

Anisotropy is inherent in many materials, either because of the manufacturing process, or due to their microstructure, and can markedly influence failure behavior. Anisotropic materials obviously possess both anisotropic elasticity fracture surface energy. Phase-field methods are elegant mathematically well-grounded, have become popular for simulating isotropic brittle fracture. Here, we develo...

Multimillion-atom molecular dynamics simulation of indentation of nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, resulting from the coexistence of brittle grains and soft amorphous grain boundary phases. Simulations predict a crossover from intergranular continuous deformation to intragrain discrete deformation at a critical indentation de...

Out-of-plane, nanoscale periodic corrugations are observed in the dynamic fracture surface of brittle bulk metallic glasses with fracture toughness approaching that of silica glasses. A model based on the meniscus instability and plastic zone theory is used to explain such dynamic crack instability. The results indicate that the local softening mechanism in the fracture is an essential ingredie...

This paper examines the microstructure and mechanical properties of Ta20Nb20Hf20Zr20Ti20. Two casting processes, namely, gravity casting and suction-assisted casting, were applied, both followed by Hot Isostatic Pressing (HIP). The aim of the current study was to investigate the creep and tensile properties of the material, since the literature review revealed no data whatsoever regarding these...

The ability to create architected materials that possess both high stiffness and toughness remains an elusive goal, since these properties are often mutually exclusive. Natural materials, such as bone, overcome such limitations by combining different toughening mechanisms across multiple length scales. Here, a new method for creating architected lattices composed of core-shell struts that are b...

Brittle materials are materials that display Hookean behavior (linear relationship between stress and strain) and which fail at a discrete strain. Plastic materials display a variety of yielding behaviors associated with changes in the internal structure of the material at a fixed level of strain and at a fixed rate of strain. The time dependence to yielding behavior is due to the structural ch...

Structural biological materials such as bone, teeth or mollusk shells draw their remarkable performance from a sophisticated interplay of architectures and weak interfaces. Pushed to the extreme, this concept leads to sutured materials, which contain thin lines with complex geometries. Sutured materials are prominent in nature, and have recently served as bioinspiration for toughened ceramics a...