Original scientific paper Based on the experimental research on three cross-shaped columns with 500 MPa grade reinforcing steel bars, the contrastive analysis is made on failure mode, bearing capacity and displacement ductility of each column specimens with different stirrup spacing under the identical axial compression ratio. The research shows that the longitudinal bars yield before spalling ...

Strength and ductility are two of the most important mechanical properties of structural materials. However, they are often mutually exclusive, i.e., a material may be strong or ductile, but rarely both at the same time. This is also true for bulk nanostructured materials, which usually have high strength, but disappointingly low ductility. Bulk nanostructured materials are usually synthesized ...

Using ab initio alloy theory, we investigate the equilibrium bulk properties and elastic mechanics of the single bcc solid-solution AlxHf1−xNbTaTiZr (x = 0–0.7, 1.0) high entropy alloys. Ab initio predicted equilibrium volume is consistent with the available experiment. We make a detailed investigation of the alloying effect of Al and Hf on the equilibrium volume, elastic constants and polycrys...

This paper is concerned with the inelastic behavior of axially loaded concrete-filled thin-walled steel tubular columns subjected to local buckling. A nonlinear fiber element analysis program accounting for local buckling effects is developed for predicting the ultimate strength and ductility of concrete-filled thin-walled steel tubular columns. The effects of local buckling are taken into cons...

Materials with ultrafine grain sizes are attractive for use in micro-forming operations. High-pressure torsion (HPT) is an effective technique that allows disc materials subjected to torsional deformation to generate microstructures with significant grain refinement. Generally, ultrafine-grained materials exhibit high strength but their ductility is limited because they have both a low rate of ...

It has been possible in recent times to make large quantities of steels in which the controlling scale is 20 nm or less, i.e., comparable to that of carbon nanotubes. The mechanical properties of such steels are abnormal. For example, in some cases the ductility vanishes as the strength increases, whereas in others the ductility almost entirely consists of uniform plastic strain. Some of the st...

High temperature tensile tests have been conducted on samples of a Fe-Ni based superalloy, Incoloy A-286, and significant ductility loss has been observed at 1220 °C. Titanium-rich, thin-film-like phase has been found on the inter-granular facets of fracture surfaces. It appears that sulfur content of Ti-rich phase was higher than that of the matrix. At 1220 °C, liquation of Ti-rich phases has ...

Abstract. The mechanical and damage behavior of a X100 steel after prestrain is studied in this work. Experimental results show both a plastic and rupture anisotropy: the T direction exhibits a higher ultimate stress but the lowest ductility and toughness. Prestrain reduces ductility and crack growth resistance. A model able to represent the plastic and damage behaviour of the material before a...

Nanostructured bainite was obtained in high-carbon Si-Al-rich steel by low-temperature (220-260 °C) isothermal transformation after austenitisation at different temperatures (900 °C, 1000 °C, and 1150 °C). Improved strength-ductility-toughness balance was achieved in the nanostructured bainitic steel austenitised at low temperatures (900 °C and 1000 °C). Increasing the austenitising temperature...

Nanotwinned metals exhibit an unusual combination of ultrahigh strength, considerable ductility and enhanced rate sensitivity. We find that a Hall–Petch-type relationship closely fits the experiment data of activation volume as a function of twin spacing. The results suggest a transition of the rate-controlling mechanism from intra-twinto twin-boundary-mediated processes with decreasing twin la...