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...

The aim of the present paper is a systematic elaboration of a three dimensional finite element analysis tool for discontinuous fracture in brittle solids. Brittle or quasi-brittle fracture usually occurs when a material reaches the limit of its strength and no plastic deformation has been observed prior to failure. In this novel approach, this kind of failure is characterized by three sets of g...

Brittle deformation can saturate the Earth's crust with faults and fractures in an apparently chaotic fashion. The details of brittle deformational histories and implications on, for example, seismotectonics and landscape, can thus be difficult to untangle. Fortunately, brittle faults archive subtle details of the stress and physical/chemical conditions at the time of initial strain localizatio...

Insight into the mechanics of brittle strain localization and fault propagation is gained by investigating the growth of deformation bands and fault–related deformation band damage zones. In porous granular rocks such as sandstone or tuff, the onset of brittle strain localization is characterized by pore space collapse along nucleating deformation bands, then by shear displacements along propag...

This paper presents an investigation of the mechanism of the brittle–ductile cutting mode transition from the perspective of the mechanics. A mechanistic model is proposed to analyze the relationship between undeformed chip thickness, deformation, and stress levels in the elastic stage of the periodic chip formation process, regarding whether brittle or ductile mode deformation is to follow the...

_Abstract. Two major hypotheses have been advanced for the formation of the long wavelength (100-300 km) undulations of oceanic basement and overlying sediments developed in the central Indian Ocean basin: whole layer folding (buckling) and local thickening (inverse boudinage). Using appropriately scaled two-layer analogue models for the oceanic lithosphere comprising a brittle layer above a du...

Constitutive laws and crystal plasticity in diamond deformation have been the subjects of substantial interest since synthetic diamond was made in 1950's. To date, however, little is known quantitatively regarding its brittle-ductile properties and yield strength at high temperatures. Here we report, for the first time, the strain-stress constitutive relations and experimental demonstration of ...

A detail field and microscopic characteristics of Malayer Plutonic Rocks (162-187Ma), west of Iran, are discussed in details to evaluate relationships between deformation and pluton emplacement. The studied rocks were injected into the slate, phyllite and schists of so called "Hamadan phyllites and slates" in the Sanandaj-Sirjan zone. Studies have shown that there is a continuity from magmatic ...

the dynamic behavior of three high manganese steels with very different stacking faultenergy (sfe) values (4-30 mj/m2) were studied using high strain rate torsional tests. the hotrolledmicrostructure of the steel with the lowest sfe of 4 mj/m2 consisted of a duplex mixture ofaustenite and ε-martensite, but those of the other two steels were fully austenitic. the deformedmicrostructures were stu...