Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Micromechanical characterization of metallic glass — crystalline nanocomposite coatings
Download
index.pdf
Date
2018
Author
Abboud, Mohammad
Metadata
Show full item record
Item Usage Stats
959
views
101
downloads
Cite This
Amorphous/crystalline nanolayers provide an effective model system to study the mechanical behavior and size effects of metallic glasses and crystalline metals in confined geometries. They also provide an advantageous structure for improving the ductility of amorphous metals while maintaining their outstanding strength. Combination of high strength and ductility make these nanocomposites promising materials as wear resistant coatings. The structure-property relationship in Amorphous/Crystalline nanolayers containing HCP crystalline layers were investigated. CuTi/Ti and CuZr/Zr nanolayers were prepared by magnetron sputtering with layer thicknesses in the range 10–100 nm. The mechanical properties of these nanolayers were investigated using nanoindentation technique, while the wear resistance of CuZr/Zr was investigated using nanoscratch technique. X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM), and High-Resolution Transmission Electron Microscopy (HRTEM) were used to characterize the structure and composition of the films. The hardness of the CuTi/Ti and CuZr/Zr nanolayers were close to those of the monolithic CuTi and CuZr, respectively. The hardness remained virtually the same for different layer thicknesses as opposed to CuTi/Cu amorphous/FCC crystalline nanolayers which exhibit increasing strength with decreasing layer thickness. The results can be explained by the confined layer slip model that predicts an effective flow stress for HCP crystalline layers higher than those of the amorphous layers. As a result, the strength and size-effects are governed by the mechanical behavior of the softer amorphous layer. The scratch resistance was the highest for the monolithic CuZr, and diminished with decreasing layer thickness for nanolayered coatings, although hardness and elastic modulus were independent of layer thickness. The nanocomposite with layer thickness of 10 nm did not show any sign of failure in spite of compressive strain exceeding 80%. Low shear strength of the CuZr-Zr interface and strain hardening of Zr layers can explain the layer thickness dependent wear resistance and outstanding damage tolerance observed. Layered metallic glass/crystalline nanocomposites combine high hardness and resistance to fracture, providing a new design space for the development of effective wear resistant coatings.
Subject Keywords
Metallic glasses.
,
Nanocomposites (Materials).
,
Coating processes.
,
Micromechanics.
,
Thin films.
URI
http://etd.lib.metu.edu.tr/upload/12622936/index.pdf
https://hdl.handle.net/11511/27942
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Size-independent strength of amorphous-HCP crystalline metallic nanolayers
Abboud, Mohammad; Özerinç, Sezer (Cambridge University Press (CUP), 2019-07-15)
Amorphous/crystalline (A/C) nanolayers provide an effective model system to study the mechanical behavior and size effects of metallic glasses and crystalline metals in confined geometries. In this work, we experimentally investigated the structure-property relationship in A/C nanolayers containing HCP crystalline layers. CuTi/Ti and CuZr/Zr nanolayers were prepared by magnetron sputtering with layer thicknesses in the range 10-100 nm. The hardness values of the CuTi/Ti and CuZr/Zr nanolayers were close to ...
Development of Nanostructured Metallic Glasses with High Toughness
Bagheri Behboud, Ali; Özerinç, Sezer; Department of Mechanical Engineering (2021-8)
Metallic glasses are metallic alloys with disordered atomic structures and desirable mechanical properties such as high hardness, high elastic limits, and wear resistance. These properties make metallic glasses promising materials for wear-resistant, corrosion-resistant, and biocompatible coating applications. On the other hand, metallic glasses are brittle, which is a major disadvantage for their use in practice. This thesis study aimed to tackle this problem through the development of nanostructured metal...
Micromechanical modeling of carbon nanotube – polymer composites
Taç, Vahidullah; Gürses, Ercan; Department of Aerospace Engineering (2018)
A micromechanics-based model is developed to simulate carbon nanotube – polymer nanocomposites and analyze its mechanical behavior. The nanocomposite is first divided into four distinct regions, or phases, based on mechanical behavior and density; the carbon nanotube, the interface, the interphase and the polymer. The finite element method was later used to combine the nanotube and interface phases into an effective fiber for better representation and incorporation of their roles and constitutive properties...
Micromechanical modelling of carbon nanotube reinforced composite materials with a functionally graded interphase
Taç, Vahidullah; Gürses, Ercan (SAGE Publications, 2019-12-01)
This paper introduces a new method of determining the mechanical properties of carbon nanotube-polymer composites using a multi-inclusion micromechanical model with functionally graded phases. The nanocomposite was divided into four regions of distinct mechanical properties; the carbon nanotube, the interface, the interphase and bulk polymer. The carbon nanotube and the interface were later combined into one effective fiber using a finite element model. The interphase was modelled in a functionally graded m...
Enhancement of Physical and Mechanical Properties of Epoxy Resins by Graphene/Graphene Oxide Additives
Budak, Deniz; Yıldırım, Erol; Department of Polymer Science and Technology (2022-1-23)
Control of interfacial interactions is essential for the preparation of polymer matrix composites with enhanced physical, mechanical, thermal and electrical properties. The performance of the graphene and graphene oxide (GO) additives can be improved by achieving strong adhesion and uniform dispersion of GO in the epoxy matrix. In this study, modeling and simulation of DGEBA (Bisphenol A diglycidyl ether)/DETA (Diethylenetriamine) based epoxy nanocomposites containing graphene and graphene oxide (GO) additi...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
M. Abboud, “Micromechanical characterization of metallic glass — crystalline nanocomposite coatings,” M.S. - Master of Science, Middle East Technical University, 2018.
