Topic
Necking
About: Necking is a research topic. Over the lifetime, 5280 publications have been published within this topic receiving 113945 citations.
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24 Feb 2014-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the tensile deformation and fracture behaviors of roll-bonded Al3003/STS439 composite were studied, and the fracture behavior was found to be induced by the resistance to neck formation of joined Al layer over the separated STS layer.
Abstract: The tensile deformation and fracture behaviors of roll-bonded Al3003/STS439 clad composite were studied. The mutual constraint and interaction of joined Al and STS with different deformation characteristics tend to shape the deformed specimen geometry to appear similar and induce the simultaneous fracture of Al and STS. The examination of the fractured clad revealed more uniform deformation of less ductile metal layer was induced by co-deforming more ductile metal layer in the clad composite, enhancing the overall tensile ductility. The suppression of neck formation in STS layer of Al3003/STS439 clad composite was observed to be induced by the resistance to neck formation of joined Al layer, rendering the enhanced ductility of joined STS layer over the separated STS layer. Excellent interface bonding and absence of brittle intermetallics at the interface are prerequisites for the enhanced ductility of clad composites because constraint by the adjacent joined metal layer can be made by the stress and strain transfer through the interface. The strength of the roll-bonded Al3003/STS439 clad composite is in close agreement with that calculated from the rule of mixture.
65 citations
TL;DR: In this article, the instability of plastic flow is analyzed in terms of the development of internal bifurcations (analogous to diffuse, multiple, external necks for non-cavitating superplastic alloys) and the linking of cavities by internal necking.
65 citations
TL;DR: In this article, a thermodynamically consistent elastic-plastic constitutive model including the von Mises yield criterion, the associated flow rule and two nonlinear isotropic hardening variables is applied to describe the behavior of the high-strength steels.
Abstract: Tensile tests on three high-strength steels exhibiting Luders band propagation are carried out at room temperature and under quasi-static loading conditions. Displacement and temperature fields on the surface of the flat samples are measured by digital image correlation and digital infrared thermography, respectively. The true stress versus true strain curves were calculated from the displacement data, while the thermal data were used to estimate the heat sources using the local heat diffusion equation. Based on these measurements the stored and dissipated energies were estimated up to diffuse necking. A thermodynamically consistent elastic-plastic constitutive model including the von Mises yield criterion, the associated flow rule and two non-linear isotropic hardening variables is applied to describe the behaviour of the high-strength steels. It is shown that this simple model is able to reproduce both the local behaviour, such as the power associated to heat sources, and the global behaviour, such as Luders band propagation and stored and dissipated energies. It is further shown that the ratio of dissipated power to plastic power varies during plastic straining and that this variation is captured reasonably well in the numerical simulations.
65 citations
TL;DR: In this paper, a UFG was subjected to equal-channel angular pressing (ECAP), which resulted in an ultra-fine-grained microstructure with an average grain size of 0.2-0.4 μm.
65 citations
TL;DR: In this paper, the implicit gradient formulation constitutes an additional partial differential equation of the Helmholtz type which is solved separately by a boundary element method (BEM), and the presented formulation is applied to a mild-steel, a Ni-based sheet-metal (INCO 718) and an aluminium alloy (AA 5182).
64 citations