The role of microstructure on hot deformation behavior of sintered Cu-28Zn prealloyed powder compacts was investigated by a series of isothermal hot compression tests in the temperature range of 550- 850°C at strain rates of 0.001, 0.01, 0.1 and 0.5 s-1, by taking into consideration the Hyperbolic Sine functional behavior to analyze the deformation behavior of the alloy. The results indicate th...

The microstructure and mechanical properties of nanocrystalline Pd films prepared by magnetron sputtering have been investigated as a function of strain. The films were deposited onto polyimide substrates and tested in tensile mode. In order to follow the deformation processes in the material, several samples were strained to defined straining states, up to a maximum engineering strain of 10%, ...

Recently, it has been reported that the morphology of Au nanoparticles (NPs) affects the catalytic activity of CO oxidation; twin crystal NPs show higher activity for CO oxidation than single-crystal NPs. In this study, density functional calculations have been carried out to investigate the morphology effect of Au NPs using CO as a probe molecule. In the case of Au NPs with a size of more than...

Martensitic crystals which can undergo a cubic to tetragonal phase transformation have a nonconvex energy density with three symmetry-related, rotationally invariant energy wells. We give estimates for the numerical approximation of a first-order laminate for such martensitic crystals. We give bounds for the L2 convergence of directional derivatives in the “twin” plane, for the L2 convergence o...

0167-9317/$ see front matter 2010 Elsevier B.V. A doi:10.1016/j.mee.2010.04.019 * Corresponding author. E-mail address: [email protected] (V. Sriram). We have performed in-situ nanocompression testing in a transmission electron microscope (TEM) of copper pillars having dimensions of the same order of typical via and line structures used in the semiconductor industry. We show direct evidence that...

Here we develop a multi-template analysis for tensor-based morphometry (TBM) which aims to reduce error from the registration step. In conventional TBM, a single template is nonlinearly registered to all images in the study, and the deformation field statistics are computed from the transformations. Using an MRI dataset from 23 monozygotic and 23 dizygotic twin pairs, we instead registered each...

The amount of twin formation of electroplated and thermally treated copper thin films was evaluated by electron back-scattering diffraction (EBSD) analysis. The result establishes the importance of twin formation in the analysis of stress-induced voiding, and indicates that with the inclusion of a copper alloy co-element, twin formation was significantly reduced relative to pure-copper. Further...

Oxygen greatly affects the mechanical properties of titanium. In addition, dislocations and twin boundaries influence the plastics deformation of hexagonal close-packed metals. As part of a systematic study of defects interactions in Ti, we investigate the interactions of oxygen with ð10 12Þ twin boundaries and ð10 10Þ prism plane stacking faults. The energetics of four interstitial sites in th...

Nanotwinned structures offer the potential to effectively enhance strength while preserving ductility and damage tolerance. In this paper we present an analytical model for quantifying slip transfer across twin boundaries and for deriving the attendant flow stress as a function of the twin lamellae size in nanotwinned face-centered cubic metals. The mechanistic models investigate how single or ...

A study has been carried out to examine effects of blast loading on the microstructure deformation response of A572 Grade 50 low carbon structural steel. Symmetrical planar impact experiments have been carried out using a single stage gas gun to drive projectiles to velocities between 200 and 500 m/sec resulting in low to moderate shock loading of disc type steel specimens. Longitudinal stress ...