Multiscale Characterization of Spatial Heterogeneity in Multiphase Composite Microstructures

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
M. A. Tschopp ◽  
G. B. Wilks ◽  
J. E. Spowart
Keyword(s):  
Spatial Heterogeneity ◽  
Reaction Yield ◽  
Length Scale ◽  
Length Scales ◽  
Phase Mixing ◽  
Multiple Length Scales ◽  
Three Phase ◽  
Reaction Stoichiometry ◽  
Multiphase Composite

A computational characterization technique is presented for assessing the spatial heterogeneity of two reactant phases in a three-phase chemically reactive composite. This technique estimates the reaction yield on multiple microstructure length scales based on the segregation of the two reactant phases and the expected reaction stoichiometry. The result of this technique is a metric, quantifying the effectiveness of phase mixing in a particular microstructure as a function of length scale. Assuming that the proportionate mixing of reactant phases on multiple length scales will enhance reaction kinetics and the overall level of reaction completion, this tool can subsequently be used as a figure-of-merit for optimizing microstructure via appropriate processing. To illustrate this point, an example is shown where a bimodal three-phase microstructure has a higher reaction yield at every length scale when compared with a monomodal three-phase microstructure with the same constituent loading.

A Multiscale Modeling Method for the Creep Behavior of SnAg Solder Alloys

2007 ◽  
Author(s):  
Min Pei ◽  
Jianmin Qu
Keyword(s):  
Multiscale Modeling ◽  
Creep Test ◽  
Eutectic Phase ◽  
Creep Model ◽  
Length Scale ◽  
Length Scales ◽  
Multiple Length Scales ◽  
Model Predictions ◽  
Snag Solder ◽  
Micrometer Size

In this paper, a microstructure-dependent creep model is developed that accounts for the hierarchal microstructure at multiple length scales. The model considers three distinguishable phases in the solder alloy at two different length scales: at the larger scale Sn dendrites of micrometer size are embedded in a homogeneous eutectic phase; at a much smaller length scale the eutectic phase consists of submicron size Ag3Sn particles embedded in a homogeneous Sn matrix. The model predictions agree well with creep test data of RE doped SnAg solders.

Fractal and Lacunarity Analyses: Quantitative Characterization of Hierarchical Surface Topographies

2016 ◽  
Vol 22 (1) ◽  
pp. 168-177 ◽  
Author(s):  
Edwin J. Y. Ling ◽  
Phillip Servio ◽  
Anne-Marie Kietzig
Keyword(s):  
Processing Parameters ◽  
Surface Structures ◽  
Quantitative Characterization ◽  
Sem Images ◽  
Length Scales ◽  
Sem Image ◽  
Multiple Length Scales ◽  
Surface Topographies ◽  
Lacunarity Analysis

AbstractBiomimetic hierarchical surface structures that exhibit features having multiple length scales have been used in many technological and engineering applications. Their surface topographies are most commonly analyzed using scanning electron microscopy (SEM), which only allows for qualitative visual assessments. Here we introduce fractal and lacunarity analyses as a method of characterizing the SEM images of hierarchical surface structures in a quantitative manner. Taking femtosecond laser-irradiated metals as an example, our results illustrate that, while the fractal dimension is a poor descriptor of surface complexity, lacunarity analysis can successfully quantify the spatial texture of an SEM image; this, in turn, provides a convenient means of reporting changes in surface topography with respect to changes in processing parameters. Furthermore, lacunarity plots are shown to be sensitive to the different length scales present within a hierarchical structure due to the reversal of lacunarity trends at specific magnifications where new features become resolvable. Finally, we have established a consistent method of detecting pattern sizes in an image from the oscillation of lacunarity plots. Therefore, we promote the adoption of lacunarity analysis as a powerful tool for quantitative characterization of, but not limited to, multi-scale hierarchical surface topographies.

Multi length scale porosity as a playground for organic thermoelectric applications

2021 ◽  
Author(s):  
Quentin Weinbach ◽  
Christian Nielsen ◽  
Laure Biniek
Keyword(s):  
Organic Materials ◽  
Length Scale ◽  
Length Scales ◽  
Materials Properties ◽  
Multiple Length Scales ◽  
Covalent Structure

Porous organic materials have interesting materials properties governed not only by their covalent structure but also by their intrinsic porosity which when controlled over multiple length scales gives rise to...

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