Correlation of microstructure and constitutive behaviour of sintered silver particles via nanoindentation

Fotuhi‐Firuzabad

et al. 2020

Sci Rep

The quantity and variety of parameters involved in the failure evolutions in solder joints under a thermo-mechanical process directs the reliability assessment of electronic devices to be frustratingly slow and expensive. To tackle this challenge, we develop a novel machine learning framework for reliability assessment of solder joints in electronic systems; we propose a correlation-driven neural network model that predicts the useful lifetime based on the materials properties, device configuration, and thermal cycling variations. The results indicate a high accuracy of the prediction model in the shortest possible time. A case study will evaluate the role of solder material and the joint thickness on the reliability of electronic devices; we will illustrate that the thermal cycling variations strongly determine the type of damage evolution, i.e., the creep or fatigue, during the operation. We will also demonstrate how an optimal selection of the solder thickness balances the damage types and considerably improves the useful lifetime. The established framework will set the stage for further exploration of electronic materials processing and offer a potential roadmap for new developments of such materials.

Section: Proposed Methodologymentioning

confidence: 99%

Correlation-driven machine learning for accelerated reliability assessment of solder joints in electronics

Fotuhi‐Firuzabad

et al. 2020

Sci Rep

Section: Introductionmentioning

confidence: 99%

“…[14] At present, the research of macroscopic constitutive and nanoindentation mainly focuses on the reverse analysis of material constitutive properties, but there are few reports on the influence of constitutive relationship on the effect of indentation hardness. [15,16] The extent of ISE usually depends on the intrinsic length scales of the material, which is attributed to the plastic strain gradient, [17] elastic recovery, work-hardening mechanisms, and high dislocation nucleation stresses underneath indentation. [13] Nix-Gao described the size effect of indentation hardness by using geometrically necessary dislocations (GNDs) and the intrinsic microstructural length scales.…”

Section: Introductionmentioning

confidence: 99%

Indentation Size Effect Model of Ti6Al4V Alloy by Combining the Macroscopic Power‐Law Constitutive Relation and Strain Gradient Theory

et al. 2022

Indentation size effect (ISE) is a critical feature for investigating the local properties of materials using the indentation test method. Although there are numerous works on the indentation response, there is a lack of data in the literature on the association between nanoindentation and uniaxial compression. Herein this study, uniaxial compression tests combined with Digital Image Correlation Technique are conducted on Ti6Al4V alloy with a focus on investigating the elastic–plastic properties and obtaining the accurately constitutive relation. Then, an ISE model of Ti6Al4V is established based on this constitutive relation and strain gradient theory. Indentation hardness, predicted by this proposed model, agrees well with the measurement by nanoindentation experimental techniques. This model can be used to bridge the gap between the uniaxial stress–strain and the depth‐dependent hardness, and clarifies the effect of the strain hardening on indentation hardness. The significance of this model is that it provides a direct and reasonable theory foundation to investigate ISE by uniaxial compression, and promotes the potential application of nanoindentation.

“…28 Even if the 3D SERS imaging technique can offer a complementary and powerful alternative on a simultaneous detection with high spatial resolution, 20,29,30 it is still under development for many applications. Furthermore, AgMSs or silver nanoparticles in microstructures have not only been exploited in the SERS application, but also in other potential applications, such as developing the performance of electrical devices, 31,32 engineering the porous materials in aerospace and construction applications, 33 and advancing materials in the semiconductor devices, 34 according to their large specific surface area, low density, and interesting catalytic and optical properties. 35,36 In these studies, the advanced characterization techniques of electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) are generally used to attain detailed information about the surface analysis of AgMSs.…”

Section: ■ Introductionmentioning

confidence: 99%

3D SERS Imaging of Nanoporous Gold–Silver Microstructures: Exploring the Formation Mechanism Based on Galvanic Replacement Reaction

et al. 2022

The potential of three-dimensional surface-enhanced Raman scattering (3D SERS) imaging has successfully been extended to investigate the transformation mechanism of metal contents in the galvanic replacement reaction of 3D nanoporous silver microstructures (AgMSs). The galvanic replacement reaction between AgMSs and Au 3+ occurs in a saturated sodium chloride solution at room temperature. The galvanized gold−silver microstructures (Au-AgMSs) with the different mole ratios of Au 3+ and AgMSs were spontaneously fabricated due to the higher reduction potential of Au 3+ than that of Ag + . 3D SERS images of AgMSs and Au-AgMSs were constructed using SERS signals of para-aminothiophenol (PATP) as a SERS probe. The Ag distribution in the microstructures was examined by microscopic and spectroscopic techniques to ensure the structural and morphological changes. 3D SERS profiles support the existence of the atomic diffusion process on the Ag template surface, corresponding to previous studies that the active site of the galvanic replacement reaction presents and forms a small hole for further replacement reaction. This process occurs simultaneously with the galvanic replacement reaction from the Ag surface to the interior of the structure. Therefore, the transformation of Ag nanoparticles inside the microstructures can be observed in the 3D SERS profile, which cannot be acquired directly from other nondestructive techniques. Furthermore, the additional information about the stability of AgMSs against the atmospheric oxidation of silver metal was discussed for a critical selection of using it as 3D SERS substrates.