Definitions Flashcards
Coefficient of thermal Expansion
The rate at which a material expands with increase in temperature with constant pressure
Covalent Bond
A type of atomic bond characterized by the sharing of an electron pair between the two atoms
Ductile
A material’s ability to bend without breaking
Anion
A negatively charged ion (would be attracted to the anode [the positively charged electrode] in electrolysis)
Martensite
A very hard form of steel that is formed when austenite is cooled very rapidly
Eutectoid
When a singular solid phase cools into two other solid phases at the same time
Ohm’s Law
V=IR, voltage, current, resistance
Isostress
A condition of constant stress
Pearlite
The combination of alpha ferrite and cementite
FCC
Face Centered Cubic, can hold 4 atoms per unit cell with a lattice constant of a = 2rsqrt(2)
Hardness
A material’s resistance to scratching, cutting, or abrasion.
Toughness
A material’s ability to withstand stress without fracturing (only deforming plastically)
Poisson’s Ratio
The ratio of how much something will get longer whenever you apply a force perpendicular to that
Bainite
Bainite is a microstructure of steel that forms when steel is cooled slower than is required to make martensite but faster than will make pearlite
Thermoplastic
A polymer that becomes moldable at a higher temperature and hardens as it cools. This must be repeatable
Cathodic Protection
A technique used to reduce corrosion of a metal surface by making it the cathode of an electrochemical cell
Tempering
To improve the hardness and elasticity of a metal by reheating it and then cooling it.
Phase
A region of material that is chemically uniform and physically distinct
Creep
Time-dependent deformation at elevated temperature and constant stress
Eutectic
When a liquid phase solidifies into two solid phases. Also the lowest possible melting point
HCP
Hexagonal-Close-Packed, a unit cell that has 6 atoms per unit cell, and a coordination number of 12
Transistor
A linear semiconductor that can control a larger current using a much smaller current
Forward Bias
A PN junction has a forward bias when current is being applied from p –> n
Flux
An effect that passes through a material or a substance
Ceramics
Brittle compounds that have a high melting temperature and are very insulative
Constructive interferance
When two waves meet in such a way where their amplitudes add to each other
Thermal conductivity
A material’s ability to conduct heat
Van der Waals bonds
The bonds form because charge is not evenly distributed in a molecule. Molecules can be slightly polar, and so they attract other molecules
True stress
The applied load divided by the actual cross-sectional area of the specimen
Scanning electron microscopy
A type of microscope that uses the scattering of a concentrated beam of electrons to image the topography of a material
Atomic packing factor
How many atoms fit in one unit cell
Hume-Rothery rules
For substitutional solid solutions:
- The atomic radii must be no more than 15% different
- The crystal structures must be similar
- The solute and solvent should have similar electronegativity
- same valency
MOSFET
An integrated circuit that uses semiconductors with a thin layer of silicon dioxide between the gate and channel
Atomic Number
The number of protons in an atom
Allotropes
When an element can exist in two or more different forms, like carbon can be graphite, charcoal, or diamond.
Galvanizing
Coating a metal with a protective layer of zinc to prevent rusting.
Resolution
The smallest distance between two points on a specimen that can still be distinguished as two separate entities
Pitting corrosion
Localized corrosion where small holes/cavities are formed in the metal
Dislocation
A crystallographic defect or irregularity within a crystal structure.
