Terms Flashcards
measures Hardenability of steels. Hardenability is a measure of the capacity of a steel to be hardened in depth when quenched from its austenitizing temperature.
Jominy Test
indicates the mechanical and/or heat treatment to which the alloy has been subjected
Temper designation
produces an increase in strength with the
attendant decrease in ductility, because the metal strain hardens; advantages over
hot working include a higher-quality surface finish, better mechanical properties
and a greater variety of them, and closer dimensional control of the finished piece
Cold Working
When deformation is achieved at a temperature above that at which recrystallization
occurs, the process is
Hot working
qualitative measure of the rate at
which hardness drops off with distance into the interior of a specimen as a result
of diminished martensite content.
Hardenability
Alloys that experience appreciable precipitation hardening at room temperature
and after relatively short time periods must be quenched to and stored under
refrigerated conditions. Several aluminum alloys that are used for rivets exhibit this
behavior
Natural aging
is carried out at
elevated temperatures.
Artificial aging
After pressing, many of the powder particles touch one another. necks form along the contact
regions between adjacent particles; in addition, a grain boundary forms within each neck, and every interstice between particles becomes a pore
Sintering
the most common method for producing ceramic components. Comprised of a mixture of the ceramic material and various organic or inorganic additives, and then to fire it in a kiln to produce a strong, vitrified object
Green body
Single Repeat unit of a polymer. 2 C-C chain bonds
Mer
is used in reference to the outline or shape of the chain molecule
Polymer conformation
This defect might be thought of as being created by removing one cation and
one anion from the interior of the crystal and then placing them both at an external
surface. Because both cations and anions have the same charge, and because for
every anion vacancy there exists a cation vacancy, the charge neutrality of the crystal
is maintained.
Schottky Defect
Upon cooling, the glass transition corresponds to the gradual
transformation from a liquid to a rubbery material and finally to a rigid solid.
The temperature at which the polymer experiences the transition from rubbery to
rigid states is termed the
Glass transition (for polymers)
Arangement of heads on a polymer
Tacticity
Chains may be composed of two or more different
repeat units, in what are termed
Copolymer
polymers, once they have hardened, will not soften
upon heating; their structures are crosslinked and network
Thermoset
sum of the atomic weight of each of the atoms in the molecules, which is present in the polymer
Molecular weight (for polymer)
A heat treatment used to precipitate a new phase from a supersaturated solid solution. For precipitation hardening, it is termed artificial aging
Precipitation heat treatment
The state of having
exactly the same numbers of positive
and negative electrical charges
Electroneutrality
A semiconductor material for which the electrical behavior is characteristic of the pure material; that is, in which electrical conductivity depends only on temperature and the band gap energy
Intrinsic Semiconductor
A semiconducting
material for which the
electrical behavior is determined by
impurities.
Extrinsic Semiconductor
For a metal, the
energy corresponding to the highest
filled electron state at 0 K.
Fermi energy
a mobile electron or hole by which electric charge passes through a semiconductor
Charge carrier
For semiconductors and insulators, a vacant electron state in the valence band that behaves as a positive charge carrier in an electric field
Hole
of the material is the ratio of the product of the resistance and area to the length of the conductor. Property of the material
Resistivity
characterises how quickly an electron can move through a metal or semiconductor, when pulled by an electric field. There is an analogous quantity for holes, called hole mobility. The term carrier mobility refers in general to both electron and hole mobility v(d) = uE
Charge carrier mobility
is the ratio of the length and cross-section area of the conductor. Property of the object
Resistance
the distance between the valence band of electrons and the conduction band. Essentially, the band gap represents the minimum energy that is required to excite an electron up to a state in the conduction band where it can participate in conduction
Electron band gap
Extrinsic semiconductors (both n- and p-type) are produced from materials that
are initially of extremely high purity, commonly having total impurity contents on
the order of 107 at%. Controlled concentrations of specific donors or acceptors
are then intentionally added, using various techniques. Such an alloying process in
semiconducting materials is termed
Doping
refers to the
small molecule from which a polymer is synthesized
Monomer
Entire Chain
Polymer
refers to the arrangement of atom positions along the chain that are not alterable except by the breaking and reforming
Configuration
It might be
thought of as being formed by a cation leaving its normal position and moving into
an interstitial site. There is no change in charge because the cation maintains the
same positive charge as an interstitial
Frenkel Defect
have linear and branched structures; they soften
when heated and harden when cooled.
Thermoplastic
