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 ...

The current experimental study is focused on the mechanical performance of masonry walls under in-plane cyclic shear forces. All specimens were fabricated with a central window, in which geometry considered recommendations Spanish structural seismic design code. Windows represent weak area structure, there are stress concentrations responsible for crack initiation. In order to improve strength ...

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...

The ductility and plastic flow behavior of highly aligned nanotwinned copper produced by interrupted magnetron sputtering is investigated. Tensile tests were performed at various strain rates at both room and liquid nitrogen (77 K) temperatures. Higher ductility and strength are reported for all samples tested at 77 K. The observed inhomogeneous deformation and shear band propagation are discus...