Hydrostatic stress

About: Hydrostatic stress is a research topic. Over the lifetime, 1568 publications have been published within this topic receiving 37773 citations.

Residual stress effect governing electromigration-based free-standing metallic micro/nanowire growth behavior

Abstract: In this study, the effect of residual stress in a film on the growth behavior of a free-standing metallic micro/nanowire due to electromigration (EM) is examined. The growth of a wire is accompanied by atomic diffusion, accumulation of atoms, and release of compressive EM-induced localized hydrostatic stress due to the accumulation of atoms. Hence, the growth of the wire dominantly depends on the EM-induced localized stress caused by the accumulation of atoms. Because rigid passivation generates a strong localized stress field in the metallic interconnect, with greater accumulation of atoms, the EM-induced localized stress state for wire growth is influenced by passivation conditions, including the thickness and residual stress associated with passivation. Two samples with different passivation thicknesses, resulting in different levels of residual stress, were used to elucidate the influence of passivation conditions on the growth performance of Al microwires. The growth rate was experimentally measured. An x-ray diffraction system was used to obtain the value of residual stress in passivation, demonstrating that a higher absolute value of compressive residual stress results in a lower growth rate. In contrast, a lower absolute value increases the growth rate of the wire and can decrease the delamination risk of the topmost passivation, deposited by sputtering. Contrarily, a passivation that is too thin, resulting in a lower absolute value of compressive stress, increases the risk of passivation crack due to the accumulation of atoms by EM. A suitable passivation thickness for a desired wire growth must be determined based on this finding.

Dynamics of virial stress in gold lattice after crack initiation

Abstract: Virial stress measures in atomistic models obtained by appropriate spatial and temporal averaging are known to be representations of continuum stresses in bulk materials. Using molecular dynamics s...

Prediction of shear angle variation in orthogonal wave-removing processes

Abstract: An analytical model is presented for predicting the dynamic response of the shear plane during an orthogonal wave-removing process. The model is derived based on the work-hardening slip-line field theory in cutting mechanics. It takes into consideration the variations of the hydrostatic stress along the shear plane and the mean frictional coefficient on the tool-chip interface in response to the change in the cutting configuration. The results from a series of simulation studies show that the predictions from the model are in very good agreement with the existing experimental evidence for a wide range of cutting conditions.

Creep of power-law material containing spherical voids

Abstract: Finite element calculations have been carried out for spherical unit cells containing a concentric spherical hole to characterize the power law creep of a material containing voids. Axisymmetric states of macroscopic stress were applied to the unit cells ranging from purely hydrostatic loading to purely deviatoric stressing. The results of the unit cell calculations are approximated well by a creep potential for the macroscopic behavior of a porous material. This potential agrees with the unit cell results for purely hydrostatic stress and purely deviatoric stress and involves a simple elliptical interpolation in between. The model predicts quite well the ratio of transverse to axial strain rate in uniaxial compression tests.