Material Science Final Review Flashcards
Which electrons in the atom of an element are primarily responsible for its chemical and physical behavior
Valence
In terms of electron structure what do all elements in Group 2A (the Alkaline earths have in common)
they contain 2 s electrons
Which quantum number determines the shape of an orbital and which describes its size (n, l, ml, or ms)
Shape - L
Size - N
In Spdf notation what is the electron configuration of the outer shell electrons in Iron (Fe)
[Ar] 4s2 3d6
What is the shape of an s orbital
Sphere
What is the electronegativity of an element a measure of?
Degree to which atoms attract electrons
What are the names of the three types of primary or strong bonding between atoms in solids ______ ______ ______
Ionic, Covalent, and Metallic
What are the four factors that affect the ion arrangement in ionic solids
Packed together as hard sphere, Charge neutrality, Non directional, and cation to anion radius ratio
What is the nature of the attractive force that holds ions together in an ionic solid
Coulombic or Electrostatic
How many electrons are shared between the two chlorine atoms in a Cl2 molecule, and what is the bond order of this bond
Number of electrons __2__
Bond Order __1st___
Where are the valence electrons of solid metals located
Electron Cloud or Free electron gas
In general how does melting temperature of an element or compound correlate to the bonding energy between the atoms or ions in it
As the bonding energy increases the melting temperature increases
What information is necessary to completely describe the space lattice of a crystal structure
The unit cell and its lattice parameters
Which of the three crystal structures of metals represent the closest packing of atoms
Face centered cubic (FCC) and hexagonal close packed (HCP)
How many atoms are therein the body centered cubic (BCC) unit cell of a metal like chromium
2 atoms per unit cell
Is an impurity atom a 0-dimensional, 1-dimensional, or 2-dimensional defect
0-dimensional or point defect
What 2 things does a Schottky defect in an ionic crystal consist of
Anion vacacncy and Cation vacancy
Are dislocations equilibrium or non equilibrium defects
Non-equilibrium defects
Are equilibrium defects theoretically present at 0 degrees Kelvin
No
What are the three elastic moduli are needed to describe the elastic behavior of a polycrystalline metal, ______ ______ and ______
Modulus of elasticity (E), Shear Modulus (G), and Poisson’s Ratio (v)
What load and what type size of indenter are required for a Rockwell B hardness test
Load:__100kg____
Indenter:____1/16_inch_diameter_steel_ball____
In two sentences describe the mechanism of plastic deformation in metals
plastic deformation in metals result primarily from slip on close packed planes in close packed directions
Slip results from the motion of dislocations by conservation motion over the slip planes
In terms of slip planes what is the source of the stored energy of cold work, that is where is the energy stored
The strain fields of the dislocation
What are the miller indices and direction indices of the slip planes and directions for the primary slip system for FCC metals
Slip planes : {111}
Slip directions : <110>
What are the three annealing stages or processes _____ _____ and _____
Recovery, Recrystallization, Grain Growth
What is the driving force for recrystallization
Stored energy of cold work
Does dislocation density increase or decrease during recrystallization
Decrease
Does grain size increase, decrease, or remain the same during recovery
Remains the same
What are the main microscopic fracture features on the center fracture surface of a cup-cone fracture of a tensile specimen of a ductile material
Dimple
What is the main microscopic brittle fracture mechanism, by which BCC metals like iron and HCP metals like zinc fail
Cleavage
What two quantities are experimentally determined in a fatigue test and then plotted on an S-N curve
Stress amplitude, and Number of cycles until failure
Which of these two quantities (Stress amplitude, and number of cycles until failure) is plotted on the Vertical axis, and what type of scale is used (linear or logarithmic)
Stress Amplitude,
Linear scale
Which of these two quantities (Stress amplitude, and number of cycles until failure) is plotted on the Horizontal axis, and what type of scale is used (linear or logarithmic)
Number of cycles until failure,
Logarithmic scale
what fundamental property is obtained from an S_N curve
Fatigue Limit
Covalent Bonding is Directional T or F
True
Hydrogen bonding between water molecules in ice is an example of Secondary Bonding T or F
False
The bonds between carbon atoms in diamond are covalent
T or F
False
The primitive HCP unit cell contains two atoms T or F
False
The {111} family of planes in FCC crystals are planes of closest packing T or F
True
The Debye-Scherrer or powder method for X-Ray diffraction uses monochromatic (constant wavelength) X-Rays T or F
True
Vacancies are 0-dimensional crystal defects T or F
True
Frick’s 1st Law describes steady-state diffusion T or F
False it is at Frick’s second law at which steady state diffusion comes into play
Interstitial Diffusion at a given temperature is much faster than vacancy mechanism diffusion T or F
True
Diffusion is a thermally activated process T or False
