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Full-Text Articles in Engineering Science and Materials

In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li Jan 2019

In Situ Mechanical Characterization Of The Mixed- Mode Fracture Strength Of The Cu/Si Interface For Tsv Structures, Chenglin Wu, Congjie Wei, Yanxiao Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In situ nanoindentation experiments have been widely adopted to characterize material behaviors of microelectronic devices. This work introduces the latest developments of nanoindentation experiments in the characterization of nonlinear material properties of 3D integrated microelectronic devices using the through-silicon via (TSV) technique. The elastic, plastic, and interfacial fracture behavior of the copper via and matrix via interface were characterized using small-scale specimens prepared with a focused ion beam (FIB) and nanoindentation experiments. A brittle interfacial fracture was found at the Cu/Si interface under mixed-mode loading with a phase angle ranging from 16.7° to 83.7°. The mixed-mode fracture ...


Mechanical Characterizations Of 3d-Printed Plla/Steel Particle Composites, Hozhabr Mozafari, Pengfei Dong, Haitham Hadidi, Michael P. Sealy, Linxia Gu Jan 2019

Mechanical Characterizations Of 3d-Printed Plla/Steel Particle Composites, Hozhabr Mozafari, Pengfei Dong, Haitham Hadidi, Michael P. Sealy, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

The objective of this study is to characterize the micromechanical properties of poly-L-lactic acid (PLLA) composites reinforced by grade 420 stainless steel (SS) particles with a specific focus on the interphase properties. The specimens were manufactured using 3D printing techniques due to its many benefits, including high accuracy, cost effectiveness and customized geometry. The adopted fused filament fabrication resulted in a thin interphase layer with an average thickness of 3 μm. The mechanical properties of each phase, as well as the interphase, were characterized by nanoindentation tests. The effect of matrix degradation, i.e., imperfect bonding, on the elastic modulus ...


Artificial Neural Network And Finite Element Modeling Of Nanoindentation Tests On Silica, Kianoosh Koocheki Jul 2018

Artificial Neural Network And Finite Element Modeling Of Nanoindentation Tests On Silica, Kianoosh Koocheki

Civil Engineering Theses, Dissertations, and Student Research

Two major forms of Silica include the crystalline form named Quartz which consist of the sand grains in nature, and amorphous form named Silica Glass or Fused Silica which is commonly known as glass. Fused Silica is an amorphous crystal that can show plastic behavior at micro-scale despite its brittle behavior in large scales. Due to the amorphous and ductile nature of Fused Silica, this behavior may not be explained well using the traditional dislocation-based mechanism of plasticity for crystalline solids. The crystal plasticity happens due to shear stress and stored energy in the material as dislocations which does not ...


Analysis Of Corrosion-Induced Diffusion Layer In Zk60a Magnesium Alloy.Pdf, Shumin Li Oct 2016

Analysis Of Corrosion-Induced Diffusion Layer In Zk60a Magnesium Alloy.Pdf, Shumin Li

Shumin Li

Corrosion-induced damage in ZK60A magnesium alloy is analyzed via chemo-mechanical tests. A certain “diffusion” corrosion layer (DCL) is identified, where partial corrosion takes place. This layer is different from the corrosion product layer (CPL). Nanoindentation analysis shows that corrosion modifies mechanical properties in the DCL, which extends up to 8–9 micrometers into the bulk, away from the CPL. Measurements over the DCL indicate a lower elastic modulus and lower fracture toughness compared with the bulk, as well as higher variance (heterogeneity). Elemental analysis confirms the layer is composed of partially oxidized magnesium and diffused chloride ions. Gradual changes in ...


Mechanical Behavior Of Nanotwinned Materials-Experimental And Computational Approaches, Hakan Yavas Jan 2016

Mechanical Behavior Of Nanotwinned Materials-Experimental And Computational Approaches, Hakan Yavas

Graduate Theses and Dissertations

Nanotwinned materials exhibit high strength combined with excellent thermal stability, making them potentially attractive for numerous applications. When deposited on cold substrates at high rates, for example, silver films can be prepared with a high-density of growth twins with an average twin boundary spacing of less than 10 nm. These films show a very strong {111} texture, with the twin boundaries being perpendicular to the growth direction. The origins of superior mechanical and thermal properties of nanotwinned materials, however, are not yet fully understood and need further improvements.

The aim of this research is to develop a connected experimental and ...


Constitutive Modeling And Experiments For The Micro And Nano Behaviors In Metals, Cheng Zhang Jan 2015

Constitutive Modeling And Experiments For The Micro And Nano Behaviors In Metals, Cheng Zhang

LSU Doctoral Dissertations

This work addresses the micro- and nano-behaviors in metals through constitutive modeling and experiments. The size effect encountered during nanoindentation experiments, which is known as indentation size effect (ISE), is investigated for metal materials. The ISE is believed to be related with the strain gradient at small indentation depths. Geometrically necessary dislocations (GNDs) are formed in order to accommodate the strain gradient, which results in the increase in the material hardness. The grain boundaries in polycrystalline materials play an important role on the material hardness during nanoindentation experiments as there is a soften-hardening segment in the curve of hardness as ...


An Atomic Force Microscopy Nanoindentation Study Of Size Effects In Face-Centered Cubic Metal And Bimetallic Nanowires, Erin Leigh Wood Jan 2014

An Atomic Force Microscopy Nanoindentation Study Of Size Effects In Face-Centered Cubic Metal And Bimetallic Nanowires, Erin Leigh Wood

Graduate College Dissertations and Theses

The enhancement of strength of nanoscale materials such as face-centered cubic metal nanowires is well known and arises largely from processes mediated by high energy surface atoms. This leads to strong size effects in nanoscale plasticity; ,smaller is stronger. Yet, other factors, such as crystalline defects also contribute greatly to the mechanical properties. In particular, twin boundaries, which are pervasive and energetically favorable defects in face-centered cubic metal nanowires, have been shown to greatly enhance the strength, furthermore this increase in strength has been shown to be directly influenced by the twin density. However, attempts to control the introduction of ...


Role Of Contamination On The Bondline Integrity Of Composite Structures, Xu Shang Jan 2013

Role Of Contamination On The Bondline Integrity Of Composite Structures, Xu Shang

Graduate Theses and Dissertations

Adhesively bonding composite structures have many applications in aerospace, automotive and submarine industries. The adhesive bonding joints have substantial advantage over the traditional metallic mechanical bonding joints, such as rivet and welding. However, the adhesive bonding joints require additional steps of surface preparation and cleaning to ensure consistent bond strength. In application, the adhesively bonded joints are exposed to environmental degradation and industrial solvent contaminates. Accordingly, the assurance of reliability of bonded composite structures requires detailed investigation of the role of contaminates on bondline integrity.

This dissertation focuses on assessing the contaminates effect on the adhesive bondline integrity. A combined ...


Experimental Study Of Ultra-Thin Films Mechanical Integrity By Combined Nano-Indentation And Nano-Acoustic Emission, Zihou Zhang Jan 2013

Experimental Study Of Ultra-Thin Films Mechanical Integrity By Combined Nano-Indentation And Nano-Acoustic Emission, Zihou Zhang

Graduate Theses and Dissertations

Advancement of interconnect technology has imposed significant challenge on interface characterization and reliability for blurred interfaces between layers. There is a need for material properties and these miniaturized length scales and assessment of reliability; including the intrinsic film fracture toughness and the interfacial fracture toughness. The nano-meter range of film thicknesses currently employed, impose significant challenges on evaluating these physical quantities and thereby impose significant challenge on the design cycle.

In this study we attempted to use a combined nano-indentation and nano-acoustic emission to qualitatively and quantitatively characterize the failure modes in ultra-thin blanket films on Si substrates or stakes ...


Methods For Characterizing Mechanical Properties Of Wood Cell Walls Via Nanoindentation, Yujie Meng Aug 2010

Methods For Characterizing Mechanical Properties Of Wood Cell Walls Via Nanoindentation, Yujie Meng

Masters Theses

Nanoindentation is a method of contacting a material whose mechanical properties are unknown with another material whose properties are known. Nanoindentation has the advantage of being able to probe a material’s microstructure while being sensitive enough to detect variations in mechanical properties. However, nanoindentation has some limitations as a testing technique due to the specific formation and structure of some biomaterials. The main objective of this research is to identify any factors that influence the nanoindentation measurement of wood cell walls (a typical biomaterial).

The function of the embedding media in describing the properties of wood cells is poorly ...


Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta Jan 2003

Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta

LSU Master's Theses

Diamondlike carbon (DLC) films have been explored extensively in the past due to their highly attractive properties. However, the high level of internal stress developed during growth prevents deposition of thick films. Synthesis of DLC/DLC multilayers (DDM) presents a venue to overcome this drawback. In the present study, DLC films and DDM were deposited on Si substrate using dc plasma of CH4 and Ar gas mixture. FTIR was used to analyze the structure of the DLC films. Mechanical properties of the films were characterized by microhardness testing and nanoindentation. The tribological properties were studied by conducting pin-on-disc experiments ...