Materials Science Flashcards
how many electrons can be held in orbitals s, p, d, and f?
2, 6, 10, 14
what are valence electrons?
outermost shell of an electron cloud
What types of elements create ionic bonds?
metals and nonmetals
What happens to electrons in ionic bonding?
They are transferred from atoms with few valence electrons to atoms that have nearly full valence electrons.
What orbitals dominate covalent bonding?
S and P
What happens to electrons in covalent bonding?
They are shared by atoms to fill shells.
What happens to electrons in metallic bonding?
Electrons freely drift around in a “sea of electrons”
what is given by the equation (1-e^-(((Xa-Xb)^2)/4))x100
Percent ionic character
What kind of bonds are in amorphous structures?
Ionic and Covalent
What kind of bonds are in crystalline structures?
metallic and ionic
How many atoms are in a Body Centered Cubic (BCC) structure?
9
How many atoms are in a Face-Centered Cubic (FCC) structure?
14
How many atoms are in a Simple Cubic (SC) structure?
8
What is the difference between BCC (body centered cubic) and BCT (body entered tetragonal)?
BCT is not a cube and has rectangular faces.
What is the equation for Atomic Packing Factor (APF)?
(volume of atoms)/(volume of unit cell)
What is the equation for theoretical density?
(nA)/(VcNa); where n is the number of atoms per unit cell, A is atomic weight, Vc is volume of the unit cell, and Na is Avigadro’s number.
Rank the density of polymers, metals, and ceramics.
metals>ceramics>polymers
What is a vacancy point defect?
when an atom is missing in the structure of a solid, so other atoms move to fill in the space.
What is a interstitial point defect?
Extra atom squeezed into lattice. Can either be the same or different.
What is the lattice direction equation of the image?
Sketch the lattice direction vector based on the equations [100], [110] and [111].
What is the lattice plane of the image?
Sketch the lattice plane of (102)
What does the equation [uvw] represent?
A lattice direction.
What does the equation (uvw) represent?
A lattice plane.
What is the equation J=-D(dC/dx)
The diffusion flux equation.
what is the equation Nv/N=e^[(-Q_D)/(kT)] used for?
Concentration of defects
What is the equation for weight percent given compounds A and B?
C_B = [(mass of B)/(total mass)]x100
What is the equation for atomic percent given compounds A and B?
C’_B = [(# atoms of B)/(total atoms)]x100
What is the equation
J = [(mass)/(areaXtime)]
used for?
Diffusion Flux in steady state diffusion
What are the properties of elastic deformation?
reversable and small load
What are the properties of plastic deformation?
permanent and small load
What is the difference between tensile engineering stress (omega) and shear engineering stress (tau)?
Tensile stress is pulling and shear is lateral pulling (sliding)
What is the lever law used for?
Determining percent compositions of various phases at a given concentration and temperature on a phase diagram.
What is the difference between eutectic and eutectoid phases?
Eutectic is higher temperature and the temperature line is when the first liquid phase forms. Eutectoid is lower temperature.
What is the reason we use engineering stress/strain rather than true stress/strain?
Because nothing will ever be “ideal” in the real world, so engineering stress/strain is more useful in practical applications.
