Introduction. Currently, nickel-titanium alloy has a noticeable spread in the mechanical engineering and mining industry. Modification of properties this by ion-implantation is also being developed. Methods materials research. For research, experimental samples Ti-Ni coarse-grained finegrained structural state were specially manufactured before after implantation with various ion beams dose D =...

The response to cyclic deformation has been studied for Cu/Cu multilayer material consisting of columns of closely spaced, parallel nanotwins. The fatigue life under stress-controlled cycling is greatly improved over that of coarse-grained Cu. Nanotwinning provides significant strengthening, which is unchanged by fatigue or severe compression. Observations by focused ion beam microscopy showed ...

We used molecular dynamics simulations with system sizes up to 100 million atoms to simulate plastic deformation of nanocrystalline copper. By varying the grain size between 5 and 50 nanometers, we show that the flow stress and thus the strength exhibit a maximum at a grain size of 10 to 15 nanometers. This maximum is because of a shift in the microscopic deformation mechanism from dislocation-...

Tribological characteristics of fine-grained WC–8 wt%Ni with different surface finishing conditions corresponding to sequential wire electrical discharge machining (wire-EDM) or grinding were investigated by performing dry reciprocating sliding experiments on TE77 pin-on-plate equipment with WC–6 wt%Co as mating material. Surface finishes and wear surfaces were characterized using surface topog...

The fatigue crack growth in a coarse-grained Fe-2 wt% Si alloy is investigated in considerable detail. At room temperature, the material is quasi-brittle and the failure mode is mixed cleavage. Under a mode-I cyclic loading, the crack can overcome the barrier effect of grain boundaries, which dominates the overall damage evolution. Associated with the geometrically necessary crack front branchi...

The sequence of shear transformation events that lead to a shear band transition in amorphous metals is described by a spatially random coarse-grained model calibrated to obey the thermodynamic scaling relations that govern flow in a real glass. The model demonstrates that shear banding is a consequence of local shear transformation events that self-organize along planes of maximum resolved she...

The influence of nanoscale reinforcement on the mechanical behavior of ultrafine-grained composites was studied. Al 5083 (Al– 4.5 Mg–0.57Mn–0.25Fe) composites, with grain size of 115 nm and B4C reinforcement size of 38 nm, were fabricated via cryomilling and consolidation. The result reveals that the presence of nanoparticles enhances strength by interacting with dislocations, while simultaneou...

For many organisms, the number of sensory neurons is largely determined during development, before strong environmental cues are present. This is despite the fact that environments can fluctuate drastically both from generation to generation and within an organism's lifetime. How can organisms get by by hard coding the number of sensory neurons? We approach this question using rate-distortion t...

The fine-grained surface material at the Apollo 11 landing site is a brownish, medium-gray, slightly cohesive granular soil, with bulky grains in the silt-to-fine-sand range, having a specific gravity of 3.1 and exhibiting adhesive characteristics. Within the upper few centimeters, the lunar soil has an average density of about 1.6 grams per cubic centimeter and is similar in appearance and beh...

The effect of the dynamic molecular rearrangements leading to compositional segregation is revealed in coarse-grained molecular dynamics simulations of short pulse laser interaction with a polymer solution in a volatile matrix. An internal release of matrix vapor at the onset of the explosive boiling of the overheated liquid is capable of pushing polymer molecules to the outskirts of a transien...