Metallic Crystal Structures Quiz
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Metallic Crystal Structures Quiz

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Questions and Answers

What process involves atoms migrating from an interstitial position to an empty one?

  • Thermal Diffusion
  • Molecular Dynamics
  • Vacancy Diffusion
  • Interstitial Diffusion (correct)

    • What does Fick's First Law relate to in the context of diffusion?

  • Mass transfer rate of elements over time (correct)
  • Volume changes during state transitions
  • Pressure dependency of materials
  • Time dependency of temperature changes

    • What is defined as the minimum temperature required for a solid to change into liquid?

  • Boiling point
  • Melting point (correct)
  • Freezing point
  • Thermal point

    • Which term describes the weight of a material, indicating heavier materials with higher values?

    <p>Density</p> Signup and view all the answers

    What mechanism describes the interchange of atoms from their regular lattice positions to vacant sites?

    <p>Vacancy Diffusion</p> Signup and view all the answers

    Which of the following represents the quantity of voids in solid materials?

    <p>Porosity</p> Signup and view all the answers

    What is the definition of Diffusion Flux?

    <p>The mass of atoms diffusing per unit area per unit time</p> Signup and view all the answers

    What type of microscopy uses an electron beam that passes through a specimen?

    <p>Transmission Electron Microscopy</p> Signup and view all the answers

    What best describes a unit cell in crystalline structures?

    <p>A basic structural unit that defines crystal composition.</p> Signup and view all the answers

    Which of the following elements is known to display a simple-cubic crystal structure?

    <p>Polonium</p> Signup and view all the answers

    In a Face-Centered Cubic (FCC) unit cell, how many total atoms are accounted for?

    <p>8 atoms</p> Signup and view all the answers

    What is the relationship for calculating the edge length (a) of a Face-Centered Cubic unit cell in terms of atomic radius (R)?

    <p>a = 2R√2</p> Signup and view all the answers

    Which of the following best describes the bonding nature in metallic crystal structures?

    <p>Non-directional and metallic bonding.</p> Signup and view all the answers

    How many types of crystal structures are specifically mentioned?

    <p>3 types</p> Signup and view all the answers

    In Hexagonal Close-Packed structures, how many atoms are on the top and bottom faces of the unit cell?

    <p>6 atoms</p> Signup and view all the answers

    What does the formula N = Ni + Nf/2 + Nc/6 represent in crystal structures?

    <p>Calculation of total number of atoms per cell.</p> Signup and view all the answers

    What is the primary purpose of a tension test?

    <p>To apply tensile load along the long axis of a specimen</p> Signup and view all the answers

    Which property of material describes its ability to absorb energy and deform plastically without fracturing?

    <p>Toughness</p> Signup and view all the answers

    What does Poisson's ratio (v) represent in material science?

    <p>The ratio of lateral strain to axial strain</p> Signup and view all the answers

    In which test is a specimen subjected to pure shear force?

    <p>Shear Test</p> Signup and view all the answers

    What characteristic of a material is defined as its ability to resist permanent shape change?

    <p>Hardness</p> Signup and view all the answers

    What does resilience in material properties refer to?

    <p>The energy absorbed during elastic deformation</p> Signup and view all the answers

    What property pertains to the ease with which a material can be deformed under compressive stress?

    <p>Malleability</p> Signup and view all the answers

    During which test does a structural member undergo twisting?

    <p>Torsion Test</p> Signup and view all the answers

    What characterizes a tilt boundary?

    <p>It is formed by aligned edge dislocations.</p> Signup and view all the answers

    Which technique is used for determining grain size by counting intersections?

    <p>Linear Intercept</p> Signup and view all the answers

    What type of boundary is characterized by a mirror lattice symmetry?

    <p>Twin Boundary</p> Signup and view all the answers

    Which of the following is a type of defect in three dimensions?

    <p>Volume Defects</p> Signup and view all the answers

    What does diffusion primarily refer to?

    <p>The process of atoms moving from high to low concentration</p> Signup and view all the answers

    Which term refers to the process where atoms from one metal diffuse into another?

    <p>Interdiffusion</p> Signup and view all the answers

    What is the basic function of optical microscopy in the context of microstructure study?

    <p>It studies microstructures using light and illumination systems.</p> Signup and view all the answers

    How are atomic vibrations related to the properties of solid materials?

    <p>They reflect the displacement of atoms out of their lattice positions.</p> Signup and view all the answers

    What characterizes steady state diffusion?

    <p>The flux remains constant and independent of time.</p> Signup and view all the answers

    What is the significance of the boiling point?

    <p>It is the minimum temperature necessary for a liquid to become gas.</p> Signup and view all the answers

    Which statement accurately describes unsteady state diffusion?

    <p>The concentration gradient is not uniform across the plate.</p> Signup and view all the answers

    How is specific gravity determined?

    <p>By comparing the density of a material to the density of a reference substance.</p> Signup and view all the answers

    What does Fick’s Second Law address?

    <p>The relationship between flux and concentration gradient over time.</p> Signup and view all the answers

    What does the term 'stress' refer to in mechanical properties?

    <p>The instantaneous load divided by the original cross-sectional area.</p> Signup and view all the answers

    What does the size and shape of a material influence?

    <p>The diffusion rate into and out of the material.</p> Signup and view all the answers

    What does 'strain' refer to in the context of materials?

    <p>The deformation experienced by a material relative to its original dimensions.</p> Signup and view all the answers

    Study Notes

    Metallic Crystal Structures

    • Metallic crystal structures are characterized by metallic bonding, which is non-directional in nature.
    • Three common crystal structures in metals are:
      • Face-Centered Cubic (FCC)
      • Body-Centered Cubic (BCC)
      • Hexagonal Close-Packed (HCP)

    Face-Centered Cubic (FCC) Crystal Structure

    • Found in metals like copper, aluminum, silver, and gold.
    • Has a cubic unit cell with atoms located at the corners and centers of all the cube faces.
    • Each unit cell contains 6 atoms.

    Body-Centered Cubic (BCC) Crystal Structure

    • Has a cubic unit cell with atoms located at the corners and one in the center of the cube.
    • Contains 2 atoms per unit cell.
    • Examples include iron, chromium, and tungsten.

    Hexagonal Close-Packed (HCP) Crystal Structure

    • Has a unit cell with a hexagonal top and bottom face with six atoms.
    • Each face is separated by a plane in the middle of the cell that contributes three additional atoms, for a total of nine atoms per unit cell.
    • Examples include magnesium, zinc, and titanium.

    Point Defects in Solid Solutions

    • Point defects are imperfections at atomic level.
    • Two common types:
      • Vacancy: A missing atom from its regular lattice position.
      • Interstitial Atom: An extra atom inserted into the crystal lattice.

    Grain Size

    • Grain size refers to the average size of the crystalline grains in a polycrystalline material.
    • Smaller grain sizes generally increase the strength and hardness of a material.

    Diffusion in Solids

    • Diffusion is the movement of atoms, ions, or molecules from a region of higher concentration to a region of lower concentration.
    • Types of diffusion:
      • Interdiffusion/Impurity Diffusion: The movement of atoms of one metal into another.
      • Self-Diffusion: The interchange of positions between atoms of the same type.

    Diffusion Mechanisms

    • Two main mechanisms:
      • Vacancy Diffusion: Atoms move to adjacent vacant lattice sites.
      • Interstitial Diffusion: Atoms move between interstitial positions in the crystal lattice.

    Fick's Laws of Diffusion

    • Fick's First Law: Describes steady-state diffusion, where the diffusion flux is constant over time.
    • Fick's Second Law: Describes unsteady-state diffusion, where the diffusion flux changes with time.

    Physical Properties of Materials

    • Physical properties describe how a material interacts with its environment. Key physical properties include:
      • Density: Mass per unit volume.
      • Porosity: The volume fraction of voids within a material.
      • Melting Point: The temperature at which a solid transforms into a liquid.
      • Boiling Point: The temperature at which a liquid transforms into a gas.
      • Specific Gravity: The ratio of the density of a material to the density of a reference material.
      • Color: The reflective property of a material.
      • Size and Shape: The dimensions of a material.

    Mechanical Properties of Materials

    • Mechanical properties describe how a material responds to applied forces. Key mechanical properties include:
      • Stress: The force acting on a unit area of a material.
      • Strain: The deformation of a material under stress.
      • Elastic Deformation: Reversible deformation that disappears when the stress is removed.
      • Plastic Deformation: Permanent deformation that remains after the stress is removed.
      • Resilience: The ability of a material to absorb energy during elastic deformation.
      • Toughness: The ability of a material to absorb energy before fracture.
      • Hardness: The material's resistance to permanent indentation.
      • Hardenability: The ability of a material to attain hardness through heat treatment.
      • Brittleness: The tendency of a material to fracture easily without significant plastic deformation.
      • Malleability: The ability of a material to deform under compressive stress without fracture.
      • Ductility: The ability of a material to deform under tensile stress without fracture.

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    Description

    Test your knowledge on metallic crystal structures, including Face-Centered Cubic (FCC), Body-Centered Cubic (BCC), and Hexagonal Close-Packed (HCP) structures. Explore the unique characteristics, examples, and configurations of these common metallic arrangements.

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