Structure & Materials Test 2

Inorganic materials that are characterized by thermal and electrical conductivities. Composed of one or more metallic elements and often also nonmetallic elements

Metals and Alloys

the branch of science and technology concerned with the properties of metals and their production and purification

Metallurgy

when was metallurgy invented

The Bronze Age

a graphical representation of the relationships among environmental constraints of temperature and composition (and sometimes pressure) and regions of ‘phase’ stability

phase diagram

A distinct form of matter, possessing the same atomic arrangement or microstructure, composition, and chemical and physical properties

phase

a chemical element of a mixture

component

The state of the system in which the phase characteristics remain constant over indefinite periods of time. At equilibrium, free energy is a minimum.

phase equilibria

the maximum concentration of solute atoms that can dissolve in a solvent – at a specific temperature.

Solubility Limit

Characterized by the number of phases present, their proportions, and the manner in which they are distributed/arranged.

Microstructure

A one-component phase diagram that displays the environmental conditions producing the three states of water

Unary Phase Diagrams

the temperature and pressure at which the solid, liquid, and vapor phases of a pure substance can coexist in equilibrium

Triple Point

A two-component phase diagram shown as a function of elemental composition and temperature

Binary Phase Diagrams

complete Liquid and Solid Solubility

Isomorphous System

On a binary phase diagram, the line or boundary separating liquid- and liquid + solid-phase fields.

Liquidus Line

On a binary phase diagram, the locus of points at which solidification is complete upon equilibrium cooling, or at which melting begins upon equilibrium heating.

Solidus Line

relating to or denoting a mixture of substances (in fixed proportions) that melts and solidifies at a single temperature that is lower than the melting points of the separate constituents or of any other mixture of them

Eutectic

one solid phase transforms to two other solid phases at a single temperature

Eutectoid reaction

upon heating, one solid phase transforms into a liquid phase and another solid phase

Peritectic Reaction

an iron alloy with a very low carbon, less than .08%, content

wrought iron

a group of iron-carbon alloys with a carbon content greater than 2%. Its usefulness derives from its relatively low melting temperature.

cast iron

A process by which a metal is extracted from its ore by a process involving heating and melting

smelting

Austenite can transform into what through slow cooling

Pearlite

Austenite can transform into what through moderate cooling

Bainite

Austenite can transform into what through rapid quenching

Martensite

When Martensite is reheated what does it become

Tempered Martensite

Particle of radius greater than critical radius, r*

Nucleus

when the nuclei form in the bulk of liquid and requires considerable supercooling

Homogeneous nucleation

much easier since a stable “nucleating surface” is present and only needs very slight supercooling

Heterogeneous nucleation

a change in the number and/or character of the phases that constitute the microstructure of an alloy

phase transformations

forms from diffusion when we heat bainite, pearlite, or martensite at temperatures just below the eutectoid temperature for long times

spheroidite

Inorganic, nonmetallic materials that consist of metallic and nonmetallic elements bonded together primarily by ionic and/or covalent bonds. Made of Cations and Anions

Ceramics

Materials consisting of long molecular chains of low-weight elements such as carbon, hydrogen, oxygen, and nitrogen. Look at polymers as carbon based and lacking long range order observed in crystalline materials.

Polymers

what materials are soft, ductile, low strengths, low density, Low thermal & electrical conductivities

Polymers

what materials are hard, brittle, and low thermal and electrical conductivities

ceramic materials

three types of crystalline polymorphic forms?

quartz, cristobalite, and tridymite

The ability of a solid material to exist in more than one form or crystal structure.

polymorphism

point defects that exist in ceramics for both cations and anions

vacancies

point defects that only exist for cations

interstitials

a cation vacancy-cation interstitial pair

Frenkel Defect

a paired set of cation and anion vacancies

Schottky Defect

both cation and anion ___ are possible when ionic size and charge must be ‘very nearly the same’

substitutional impurities

he most fundamental structural unit in a polymer chain. A polymer molecule is composed of a large number of repeat units linked together.

repeat unit

Produced by repeat units joined together end-to-end into single chains; Akin to spaghetti noodles.

Linear Polymer

Synthesized in which side-chains are connected to the main molecular chain

Branched Polymers

When adjacent linear chains are joined one to another at various positions by covalent bonds

Cross-linked polymers

A semicrystalline polymeric material that softens when heated and hardens upon cooling.

Thermoplastic polymer

A polymeric material that, once having been cured (or hardened) by a chemical reaction, will not soften or melt when subsequently heated.

Thermosetting polymer

A primary interatomic bond involving the non-directional sharing of delocalized valence electrons (sea of electrons) that are shared by all the atoms in the metallic solid.

Metallic Bonding

Resistivity, p(rho)

a material property that is independent of sample size and geometry

a measure of the ease with which a material is capable of conducting an electrical current

electrical conductivity

pure material semiconductors like silicon and germanium, use both the mu of electrons and holes

Intrinsic semiconduction

electrical behavior is determined by presence of impurities that introduce excess electrons. conductivity solved using mu of electrons

n-type extrinsic semiconduction

Electrical behavior is determined by presence of impurities that introduce excess holes. conductivity solved using mu of holes

p-type extrinsic semiconduction

a quantity that represents the magnetic strength and orientation of a magnet or other object that produces a magnetic field.

magnetic moment

very weak form of magnetism that is nonpermanent and only persists under an applied magnetic field. induced by a change in the orbital motion of electrons due to the applied magnetic field

diamagnetism

weak form of magnetism that results from the independent alignment of atomic dipoles and only persists under an applied magnetic field. induced by atomic dipoles that are free to rotate and align in an applied magnetic field

paramagnetism

Permanent and large magnetizations found in some metals resulting from the parallel alignment of neighboring magnetic moments. Iron, Cobalt, and Nickel

Ferromagnetism

a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization.

magnetostriction

Permanent and large magnetizations found in some ceramic materials resulting from antiparallel spin coupling and incomplete magnetic moments cancelation

Ferrimagnetism

compound where magnetic moments of ions in the octahedral sites oppose the magnetic moments of ions in tetrahedral sites – but there is a net magnetic field

magnetite

a naturally magnetized piece of the mineral magnetite.

Lodestone

small volume regions where there is mutual alignment in same direction of all magnetic dipole moments

Domains

what is explained by the motion of the domain walls

Hysteresis Effect