1 Size effects 1 MTX9100 Nanomaterials Lecture 6 OUTLINE -Why does size influence the material s properties? -How does size influence the material s performance? -Why are properties of nanoscale objects different than those of the same materials at the bulk scale? -Why nanomaterials are unstable?
2 Size-dependent properties At the nanometer scale, properties become size-dependent. For example, (1) Chemical properties reactivity, catalysis (2) Thermal properties melting temperature (3) Mechanical properties adhesion, capillary forces (4) Optical properties absorption and scattering of light (5) Electrical properties tunneling current (6) Magnetic properties superparamagnetic effect 2 New properties enable new applications
3 Materials structures Most materials are made up of ordered crystals that meet at disordered boundaries; the crystals in nanomaterials are only ,000 atoms across. Amorphous or glassy materials are totally disordered; the only characteristic dimension is that of the atoms or molecules that make them up. They are an extreme from of nanomaterial. 3
4 4 Thermal property - Melting point
5 Thermal property - Melting temperature Melting Point (Microscopic Definition) Temperature at which the atoms, ions, or molecules in a substance have enough energy to overcome the intermolecular forces that hold the them in a fixed position in a solid At macroscopic length scales, the melting temperature of materials is size-independent. For example, an ice cube and a glacier both melt at the same temperature. 5
6 Thermal properties Nanocrystal size decreases In contact with 3 atoms surface energy increases melting point decreases In contact with 7 atoms Surface atoms require less energy to move because they are in contact with fewer atoms of the substance 6 Example: 3 nm CdSe nanocrystal melts at 700 K compared to bulk CdSe at 1678 K
7 7 Melting point as a function of size
8 Thermal transport Heat is transported in materials by two different mechanisms: lattice vibration waves (phonons) and Free electrons. In metals, the electron mechanism of heat transport is significantly more efficient than phonon processes. In the case of nonmetals, phonons are the main mechanism of thermal transport. In both metals and nonmetals, as the system length scale is reduced to the nanoscale, there are quantum confinement and classical scattering effects. 8
9 Quantum confinement The presence of nearby surfaces in 0-D, 1-D, and 2-D nanostructures causes a change in the distribution of the phonon frequencies as a function of phonon wavelength as well as the appearance of surface phonon modes. These processes lead to changes in the velocity with which the variations in the shape of the wave s amplitude propagate, the so-called group velocity. The phonon lifetime is modified due to phonon-phonon interaction and free surface and grain boundary scattering. 9
10 Thermal property - Conductivity where v is a particle velocity, l is a free path length, С = сn is a heat capacity of unit volume, c is a heat capacity of single particle, n is a number of particles 10
11 Mechanical Properties At the nanoscale, surface and interface forces become dominant. For example, These forces can exceed (1) Adhesion forces (2) Capillary forces forces that are normally (3) Strain forces dominant at macroscopic length scales 11
12 Mechanical properties Relative to microstructural (MSM) metals and alloys, the NSM contain a higher fraction of grain boundary volume (for example, for a grain size of 10 nm, between 14 and 27% of all atoms reside in a region within nm of a grain boundary); therefore, grain boundaries play a significant role in the materials properties. 12 Changes in the grain size result in a high density of incoherent interfaces or other lattice defects such as dislocations, vacancies, etc. As the grain size d of the solid decreases, the proportion of atoms located at or near grain boundaries relative to those within the interior of a crystalline grain, scales as 1/d. This has important implications for properties in ultra-finegrained materials which will be principally controlled by interfacial properties rather than those of the bulk.
13 Grain boundaries Crystals contain internal interfacial defects, know as grain boundaries, where the lattice orientation changes The misfit between adjacent crystallites in the grain boundaries changes the atomic structure (e.g. the average atomic density, the nearestneighbor coordination, etc.) of materials. At high defect densities the volume fraction of defects becomes comparable with the volume fraction of the crystalline regions. In fact, this is the case if the crystal diameter becomes comparable with the thickness of the interfaces. Non equilibrium materials 13 DEFECTS!!!
14 Crystals always contain defects Vacancies are point defects in the crystalline structure of a solid that may control many physical properties in materials such as conductivity and reactivity. However, nanocrystals are predicted to be essentially vacancy-free; their small size precludes any significant vacancy concentration. This result has important consequences for all thermo mechanical properties and processes (such as creep and precipitation) which are based on the presence and migration of vacancies in the lattice. Point defects: 0.1 nm (10-10 m) 14
15 Impurity atoms 15 Material properties can be altered significantly through the addition of impurity atoms
16 Glossary Point defects - Imperfections, such as vacancies, that are located typically at one (in some cases a few) sites in the crystal. Extended defects - Defects that involve several atoms/ions and thus occur over a finite volume of the crystalline material (e.g., dislocations, stacking faults, etc.). Vacancy - An atom or an ion missing from its regular crystallographic site. Interstitial defect - A point defect produced when an atom is placed into the crystal at a site that is normally not a lattice point. Substitutional defect - A point defect produced when an atom is removed from a regular lattice point and replaced with a different atom, usually of a different size. 16
17 Summary of point defects (c) 2003 Brooks/Cole Publishing / Thomson Learning 17 (a) vacancy, (b) interstitial atom, (c) small substitutional atom, (d) large substitutional atom, (e) Frenkel defect, (f) Schottky defect.
18 Defects for plasticity Crystals all contain line defects known as dislocations Dislocations act as the main source of plastic deformation in crystalline materials 18
19 Plastic deformation (a) When a shear stress is applied to the dislocation in (a), the atoms are displaced, causing the dislocation to move one Burgers vector in the slip direction (b). Continued movement of the dislocation eventually creates a step (c), and the crystal is deformed. (Adapted from A.G. Guy, Essentials of Materials Science, McGraw-Hill, 1976.) (d) Motion of caterpillar is analogous to the motion of a dislocation. 19
20 Dislocations Dislocations are positioned closer together and dislocations movement in the net is hindered by interaction between them. Together with the reduced elastic strain energy, this fact results in dislocations that are relatively immobile and the imposed stress necessary to deform a material increases with decrease in grain size. 20 Dislocations have a less dominant role to play in the description of the properties of nanocrystals. The free energy of a dislocation is made up of a number of terms: (i) the core energy (within a radius of about three lattice planes from the dislocation core); (ii) the elastic strain energy outside the core and extending to the boundaries of the crystal, and (iii) the free energy arising from the entropy contributions. In mc the first and second terms increase the free energy and are by far the most dominant terms. Hence dislocations, unlike vacancies, do not exist in thermal equilibrium.
21 Increase in strengths and hardness The relation between yield stress and grain size is described mathematically by the Hall-Petch equation 21 where k y is the strengthening coefficient (a constant unique to each material), σ o is a materials constant for the starting stress for dislocation movement (or the resistance of the lattice to dislocation motion), d is the grain diameter, and σ y is the yield stress.
22 Grain boundary strengthening Grain boundary strengthening (or Hall-Petch strengthening) is a method of strengthening materials by changing their average grain size. It is based on the observation that grain boundaries impede dislocation movement and that the number of dislocations within a grain have an effect on how easily dislocations can traverse grain boundaries and travel from grain to grain. So, by changing grain size one can influence dislocation movement and yield strength This is a schematic roughly illustrating the concept of dislocation pile up and how it effects the strength of the material. A material with larger grain size is able to have more dislocation to pile up leading to a bigger driving force for dislocations to move from one grain to another. Thus you will have to apply less force to move a dislocation from a larger than from a smaller grain, leading materials with smaller grains to exhibit higher yield stress.
23 Hall-Petch strengthening limit Hall-Petch Strengthening is limited by the size of dislocations. Once the grain size reaches about 10 nm, grain boundaries start to slide. 23
24 Ductility Deformation and fracture of ultra-high-fine materials: (a) Plastic flow localization; (b) nanockrack nucleation; (c) final failure Fracture surface of a 30 nm grain size electrodeposited Ni tensile specimen. 24
25 Deformation of nano-metal 25 from Kumar et al., Acta Materialia, 2003, v.51,
26 How to improve ductility? NC materials with high ductility: (a) a bimodal single-phase structure composed of nanograins and large grains; and (b) nano-composite consisting of nanoscale grains and dendrite like inclusions of the second phase (from I.A. Ovid ko, Rev. Adv. Mater. Sci., 2005, v.10, ). 26
27 27 Nanostructured solids
28 Why nanostructured polycrystalline materials are unstable? GB consists of several types of extrinsic defects, namely, stationary dislocations with Burgers vectors normal to a boundary plane, gliding or tangential dislocations with Burgers vectors tangential to the boundary plane, and disclinations in triple junctions. Disclinations and grain boundary dislocations form elastically distorted layers (zones) near grain boundaries. 28 High density of defects -> High energy Nature -> seek to lower energy Grain growth occurs in materials to reduce the overall energy of the system by reducing the total grain boundary energy. Therefore, grain growth in NC materials is primarily driven by the excess energy stored in the grain or interphase boundaries.
30 Pileups in a grain and a layer of a nanolayer structure 30
31 31 Hardness
32 Nanoscale optical properties Bulk gold appears yellow in color Nanosized gold appears red in color The particles are so small that electrons are not free to move about as in bulk gold Because this movement is restricted, the particles react differently with light 32 Optical properties are connected with electronic structure, a change in zone structure leads to a change in absorption and luminescence spectra.
34 34 Surface plasmon absorption Surface plasmon absorption of spherical nanoparticles and its size dependence. (a) A schematic illustrating the excitation of the dipole surface plasmon oscillation. The electric field of an incoming light wave induces a polarization of the (free) conduction electrons with respect to the much heavier ionic core of a spherical metal nanoparticle. A net charge difference is only felt at the nanoparticle surfaces, which in turn acts as a restoring force. In this way a dipolar oscillation of the electrons is created with period T. (b) Optical absorption spectra of 22, 48 and 99nm spherical gold nanoparticles. The broad absorption band corresponds to the surface plasmon resonance (from S. Link, M.A. El-Sayed Int. Rev. Phys. Chem. 2000, v.19, 409)
35 optical properties Transformation of absorption spectra of sodium from atom to solid 35 Absorption (fluorescence) spectrum of Na atom relates to the transition 2S 2P. The spectrum of Na3 cluster expands into the discrete molecular spectrum reflecting electron excitations and atom oscillations. Continuous spectrum of Na8 cluster reflects the processes of dissociations and defragmentation of cluster on atoms. Spectrum of nanoparticle reflects resonance absorption of cluster atoms. Spectrum of massive film reflects the interband transitions of electrons in metal. Optical absorption spectra of sodium: а) for atom, b) for cluster Na3, c) for cluster Na8, d) for nanoparticle of d<10 nm size (~10 6 atoms) in NaCl crystal, e) for thin film of d=10 nm width.
36 Blue shift Blue shift refers to a shortening of a transmitted signal's wavelength, and/or an increase in its frequency. The name comes from the fact that the shorter-wavelength end of the optical spectrum is the blue end, hence, when visible light is compacted in wavelength, it is "shifted towards the blue", or "blue-shifted". Blue shift phenomenon is a quantum size effect. W is a work function, EF is a Fermi energy, HOMO is the highest occupied molecular orbital, LUMO is the 36lowest unoccupied molecular orbital Transformation of zone structure of a solid under reduction of its size from macroto nano-scale down to a single atom, showing the increase of the band gap g E and the blue shift hω = E for nanoparticles and nanostructured state of matter.
37 The properties of MC and NC materials of the same chemical composition 37
38 In the quantum world, the rules are different. The classical world The quantum world 38
39 Quantum tunneling A nanoscopic phenomenon in which a particle violates the principles of classical mechanics by penetrating a potential barrier or impedance higher than the kinetic energy of the particle. 39 Electron tunneling is attained when a particle with lower energy is able to exist on the other side of an energy barrier with higher potential energy.
40 Go through the wall Tunneling is the penetration of an electron into a classically forbidden region. A barrier, in terms of quantum tunneling, may be a form of energy state analogous to a "hill" or incline in classical mechanics, which classically suggests that passage through or over such a barrier would be impossible without sufficient energy. 40
41 The principal of quantum tunneling Electrons exhibit wave behavior and their position is presented by a wave (probability) function. The wave function represents a finite probability of finding an electron on the other side of the potential barrier. Since the electron does not posses enough kinetic energy to overcome the potential barrier, the only way the electron can appear on the other side is by tunneling through 41 the barrier.
Chapter Outline Dislocations and Strengthening Mechanisms What is happening in material during plastic deformation? Dislocations and Plastic Deformation Motion of dislocations in response to stress Slip
Chapter Outline Dislocations and Strengthening Mechanisms What is happening in material during plastic deformation? Dislocations and Plastic Deformation Motion of dislocations in response to stress Slip
Free Electrons in a Metal - in a typical metal each atom contributes one electron to the delocalized electron gas describing the conduction electrons - if these electrons would behave like an ideal gas
Chemical Synthesis Spontaneous organization of molecules into stable, structurally well-defined aggregates at the nanometer length scale. Overview The 1-100 nm nanoscale length is in between traditional
Advanced Materials Science - Lab Intermediate Physics University of Ulm Solid State Physics Department Electrical Conductivity Translated by Michael-Stefan Rill January 20, 2003 CONTENTS 1 Contents 1 Introduction
MME131: Lecture 8 Imperfections in atomic arrangements Part 1: 0D Defects A. K. M. B. Rashid Professor, Department of MME BUET, Dhaka Today s Topics Occurrence and importance of crystal defects Classification
1.5 Light absorption by solids Bloch-Brilloin model L e + + + + + allowed energy bands band gaps p x In a unidimensional approximation, electrons in a solid experience a periodic potential due to the positively
Energy Transport Focus on heat transfer Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids) Conduction Conduction heat transfer occurs only when there is physical contact
Modern Construction Materials Prof. Ravindra Gettu Department of Civil Engineering Indian Institute of Technology, Madras Module - 2 Lecture - 2 Part 2 of 2 Review of Atomic Bonding II We will continue
Tunnel Effect: - particle with kinetic energy E strikes a barrier with height U 0 > E and width L - classically the particle cannot overcome the barrier - quantum mechanically the particle can penetrated
Covalent Crystals - covalent bonding by shared electrons in common orbitals (as in molecules) - covalent bonds lead to the strongest bound crystals, e.g. diamond in the tetrahedral structure determined
Lösungen Übung Verformung 1. (a) What is the meaning of T G? (b) To which materials does it apply? (c) What effect does it have on the toughness and on the stress- strain diagram? 2. Name the four main
-138- Lecture 18 Strain Hardening And Recrystallization Strain Hardening We have previously seen that the flow stress (the stress necessary to produce a certain plastic strain rate) increases with increasing
Strengthening The ability of a metal to deform depends on the ability of dislocations to move Restricting dislocation motion makes the material stronger Mechanisms of strengthening in single-phase metals:
Module #17 Work/Strain Hardening READING LIST DIETER: Ch. 4, pp. 138-143; Ch. 6 in Dieter D. Kuhlmann-Wilsdorf, Trans. AIME, v. 224 (1962) pp. 1047-1061 Work Hardening RECALL: During plastic deformation,
Chapter Outline iffusion - how do atoms move through solids? iffusion mechanisms Vacancy diffusion Interstitial diffusion Impurities The mathematics of diffusion Steady-state diffusion (Fick s first law)
Epitaxy Epitaxial Growth Epitaxy means the growth of a single crystal film on top of a crystalline substrate. For most thin film applications (hard and soft coatings, optical coatings, protective coatings)
Crystal Defects p. 1 A two-dimensional representation of a perfect single crystal with regular arrangement of atoms. But nothing is perfect, and structures of real materials can be better represented by
MSE 528 - PRECIPITATION HARDENING IN 7075 ALUMINUM ALLOY Objective To study the time and temperature variations in the hardness and electrical conductivity of Al-Zn-Mg-Cu high strength alloy on isothermal
Basic types of solid materials. Overview The theory of bands provides a basis for understanding the classification and physical properties of solid materials such as electrical conductivity, optical behavior
Free Electron Fermi Gas (Kittel Ch. 6) Role of Electrons in Solids Electrons are responsible for binding of crystals -- they are the glue that hold the nuclei together Types of binding (see next slide)
Material Strengthening Mechanisms Academic Resource Center Agenda Definition of strengthening Strengthening mechanisms Grain size reduction Solid solution alloying Cold Working (strain hardening) Three
Lecture 6 Scanning Tunneling Microscopy (STM) General components of STM; Tunneling current; Feedback system; Tip --- the probe. Brief Overview of STM Inventors of STM The Nobel Prize in Physics 1986 Nobel
Fatigue :Failure under fluctuating / cyclic stress Under fluctuating / cyclic stresses, failure can occur at loads considerably lower than tensile or yield strengths of material under a static load: Fatigue
Lecture 09 Dislocations & Strengthening Mechanisms Chapter 7-1 Dislocations & Strengthening Mechanisms ISSUES TO ADDRESS... Why are dislocations observed primarily in metals and alloys? How are strength
Lecture 3: Optical Properties of Bulk and Nano 5 nm The Previous Lecture Origin frequency dependence of χ in real materials Lorentz model (harmonic oscillator model) 0 e - n( ) n' n '' n ' = 1 + Nucleus
Materials 101 Introduction to Structure and Properties Winter 005 Final Exam March 17, 005 Solutions TOTAL POINTS 37 Problem 1: Tensile Test and Plastic Deformation (10 Points) A copper rod is deformed
Electron Beam Specimen Interaction The interaction of a high energy electron beam with the specimen will produce various effects resulting in a range of signals being emitted. The incident electrons interact
Laboratory 1 Tensile Testing Objectives Students are required to understand the principle of a uniaxial tensile testing and gain their practices on operating the tensile testing machine. Students are able
Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP6, Kinetics and Microstructure Modelling, H. K. D. H. Bhadeshia Lecture 3: Introduction to Diffusion Mass transport in
Material Science Prof. Satish V. Kailas Associate Professor Dept. of Mechanical Engineering, Indian Institute of Science, Bangalore 5612 India Chapter 15. Thermal properties Engineering materials are important
Lecture 2: Semiconductors: Introduction Contents 1 Introduction 1 2 Band formation in semiconductors 2 3 Classification of semiconductors 5 4 Electron effective mass 10 1 Introduction Metals have electrical
Grade 8 Science Vocabulary The Florida Comprehensive Assessment Test Specifications for Science provides a glossary of vocabulary words identified by Florida educators as essential to assessing the Science
Material Deformations Academic Resource Center Agenda Origin of deformations Deformations & dislocations Dislocation motion Slip systems Stresses involved with deformation Deformation by twinning Origin
Strengthening Mechanisms Design Principle Increase the intrinsic resistance to dislocation motion. Generally, ductility suffers when strength increases! Possible Ways Dislocation interaction with 1) other
Matter, Materials, Crystal Structure and Bonding Chris J. Pickard Why should a theorist care? Where the atoms are determines what they do Where the atoms can be determines what we can do Overview of Structure
Materials Science and Engineering Department MSE 200-001, Sample Test #1, Spring 2010 ID number First letter of your last name: Name: No notes, books, or information stored in calculator memories may be
MTE 585 Oxidation of Materials Part 1 Ref. Ch. 11 in Superalloys II Ch. 8 in Khanna Ch. 14 in Tien & Caulfield Introduction To illustrate the case of high temperature oxidation, we will use Ni-base superalloys.
Materials Issues in Fatigue and Fracture 5.1 Fundamental Concepts 5.2 Ensuring Infinite Life 5.3 Finite Life 5.4 Summary FCP 1 5.1 Fundamental Concepts Structural metals Process of fatigue A simple view
Metallic Bond Definition : It may be defined as, 1. The force that binds a metal ion to a number of electrons with in its sphere of influence. 2. The attractive force which holds the atoms of two or more
1. Fundamentals of grain boundaries and grain boundary migration 1.1. Introduction The properties of crystalline metallic materials are determined by their deviation from a perfect crystal lattice, which
Electrical properties Electrical conduction How many moveable electrons are there in a material (carrier density)? How easily do they move (mobility)? Semiconductivity Electrons and holes Intrinsic and
Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP6, Kinetics and Microstructure Modelling, H. K. D. H. Bhadeshia Lecture 4: Thermodynamics of Diffusion: Spinodals Fick
Ch. 4: Imperfections in Solids Part 1 Dr. Feras Fraige Outline Defects in Solids 0D, Point defects vacancies Interstitials impurities, weight and atomic composition 1D, Dislocations edge screw 2D, Grain
Solution for Homework #1 Chapter 2: Multiple Choice Questions (2.5, 2.6, 2.8, 2.11) 2.5 Which of the following bond types are classified as primary bonds (more than one)? (a) covalent bonding, (b) hydrogen
Name: Class: Date: ID: A Unit 12 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) A solid has a very high melting point, great hardness, and
Concept 1: Properties of Objects and Materials Classify objects and materials by their observable properties. Kindergarten Grade 1 Grade 2 Grade 3 Grade 4 PO 1. Identify the following observable properties
Notice TPA (AFM) Scanning Probe Microscopy Résumé R. Sanjinés Date: 09.09.2014 SCANNING PROBE MICROSCOPY: Study of surfaces by 3- Dimentional images I Introduction Atomic Force Microscopy (AFM) The Atomic
Structure of materials The atomic number is the number of protons for each element. Atoms of the same element have the same number of protons in the nucleus but may differ by one or more neutrons forming
5. Scanning Near-Field Optical Microscopy 5.1. Resolution of conventional optical microscopy Resolution of optical microscope is limited by diffraction. Light going through an aperture makes diffraction
7-1 CHAPTER 7 DISLOCATIONS AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS Basic Concepts of Dislocations Characteristics of Dislocations 7.1 The dislocation density is just the total dislocation length
CHAPTER 7: DISLOCATIONS AND STRENGTHENING ISSUES TO ADDRESS... Why are dislocations observed primarily in metals and alloys? Mech 221 - Notes 7 1 DISLOCATION MOTION Produces plastic deformation, in crystalline
Physics 551: Solid State Physics F. J. Himpsel Background Most of the objects around us are in the solid state. Today s technology relies heavily on new materials, electronics is predominantly solid state.
THE WAY TO SOMEWHERE Sub-topics 1 Diffusion Diffusion processes in industry RATE PROCESSES IN SOLIDS At any temperature different from absolute zero all atoms, irrespective of their state of aggregation
A8 Thermal properties of materials Thermal properties the melting temperature, T m, and the glass temperature (temperatura de transição vítrea), T g, relate directly to the strength of the bonds in the
Acoustics 8 Paris Plate waves in phononic crystals slabs J.-J. Chen and B. Bonello CNRS and Paris VI University, INSP - 14 rue de Lourmel, 7515 Paris, France email@example.com 41 Acoustics 8 Paris We
Griffith theory of brittle fracture: Observed fracture strength is always lower than theoretical cohesive strength. Griffith explained that the discrepancy is due to the inherent defects in brittle materials
Wave Properties of Electromagnetic Radiation Two options are available for analytical utility when an analyte interacts with a beam of electromagnetic radiation in an instrument 1. We can monitor the changes
Lecture 12 Physical Vapor Deposition: Evaporation and Sputtering Reading: Chapter 12 Evaporation and Sputtering (Metalization) Evaporation For all devices, there is a need to go from semiconductor to metal.
Acoustic Velocity, Impedance, Reflection, Transmission, Attenuation, and Acoustic Etalons Acoustic Velocity The equation of motion in a solid is (1) T = ρ 2 u t 2 (1) where T is the stress tensor, ρ is
DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS Quantum Mechanics or wave mechanics is the best mathematical theory used today to describe and predict the behaviour of particles and waves.
Lecture: 33 Solidification of Weld Metal This chapter presents common solidification mechanisms observed in weld metal and different modes of solidification. Influence of welding speed and heat input on
FATIGUE CONSIDERATION IN DESIGN OBJECTIVES AND SCOPE In this module we will be discussing on design aspects related to fatigue failure, an important mode of failure in engineering components. Fatigue failure
Nano water Demonstration: Light Interactions with Dye Molecules and Nanomaterials Key Concepts: In this module, students are expected to learn: How the light can be absorbed or scattered by small objects
Introduction Until the early 20 th century physicists used to explain the phenomena in the physical world around them using theories such a mechanics, electromagnetism, thermodynamics and statistical physics
NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2011, 2 (2), P. 76 83 UDC 538.97 MOLECULAR DYNAMICS INVESTIGATION OF DEFORMATION RESPONSE OF THIN-FILM METALLIC NANOSTRUCTURES UNDER HEATING I. S. Konovalenko
Synopsis Name of the student: Piyush Jagtap Department: Materials Engineering, Indian Institute of Science, Bangalore-12 Degree registered: PhD S. R. No.: 05-09-00-10-12-11-1-08910 Title of the thesis:
9.4.4 Investigations into the electrical properties of particular metals at different temperatures led to the identification of superconductivity and the exploration of possible applications 9.4.4-2(i)
Yang-Yuan Chen Low temperature and nanomaterial labatory Institute of Physics, Academia Sinica E-mail : Cheny2@phys.sinica.edu.tw http://www.phys.sinica.edu.tw/%7elowtemp/ Introduction: 1. Metal Nanoclusters
Quantum Theory and Atomic Structure Nuclear atom small, heavy, positive nucleus surrounded by a negative electron cloud Electronic structure arrangement of the electrons around the nucleus Classical mechanics
7. Gases, Liquids, and Solids 7.1 Kinetic Molecular Theory of Matter Kinetic Molecular Theory of Matter The Kinetic Molecular Theory of Matter is a concept that basically states that matter is composed
Work Hardening Dislocations interact with each other and assume configurations that restrict the movement of other dislocations. As the dislocation density increases there is an increase in the flow stress
Crystals are like people, it is the defects in them which tend to make them interesting! - Colin Humphreys. Defects in Solids Chapter Outline 0D, Point defects vacancies interstitials impurities, weight
FYS3410 - Vår 2014 (Kondenserte fasers fysikk) http://www.uio.no/studier/emner/matnat/fys/fys3410/v14/index.html Pensum: Solid State Physics by Philip Hofmann (Chapters 1-7 and 11) Andrej Kuznetsov delivery
SYNTHESIS AND ANALYSIS OF SILVER/GOLD NANOPARTICLES Background Shelby Hatch and George Schatz Northwestern University, Evanston, IL 60208 All physical and chemical properties are size dependent, and the
Training Objective After watching this video and reviewing the printed material, the student/trainee will learn the basic concepts of the heat treating processes as they pertain to carbon and alloy steels.
Electronic Structure and the Periodic Table Learning Outcomes (a) Electronic structure (i) Electromagnetic spectrum and associated calculations Electromagnetic radiation may be described in terms of waves.
: Diffusion Diffusion: the movement of particles in a solid from an area of high concentration to an area of low concentration, resulting in the uniform distribution of the substance Diffusion is process
Crystalline solids A solid crystal consists of different atoms arranged in a periodic structure. Crystals can be formed via various bonding mechanisms: Ionic bonding Covalent bonding Metallic bonding Van
Diffusion MSE 21 Callister Chapter 5 1 Goals: Diffusion - how do atoms move through solids? Fundamental concepts and language Diffusion mechanisms Vacancy diffusion Interstitial diffusion Impurities Diffusion
Problem Set 7 Materials101 1.) You wish to develop a gold alloy (mostly gold) that can be precipitation strengthened to provide high strength - high conductivity electrical leads to integrated circuits