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Notes on video lecture:
Dislocations Explain Plastic Deformation
Choose from these words to fill the blanks below:
stiffness, resist, temperature, semiconductors, microscopic, elastomers, macroscopic, cracks, quantifying, ceramics, magnitude, squeezed, force, cubic, carbon, desired, metallic, original, properties, faults, Burgers, fatigue
six materials that engineers have to work with:
1. metals
2. polymers
3.                 
4. glass
5. fiberglass
6.                             
in each case there is a difference at a very low level
e.g. in the case of fiberglass, the                        architecture of the fiber-reinforced composite
underlying principle
a mantra of material science: structure leads to                     
differences at the atomic or microscope level lead to differences at the                        or engineering level
stress-strained curve
early concept of atomic bonding led to characteristic of                   
bonding force curve is the first derivative of the bonding energy curve
two              atoms in a polymer
two aluminum atoms in a aluminum alloy
the difference between an aluminum and oxygen ion in an aluminum oxide
at the atomic scale, we are trying to tear atoms apart
a macroscopic scale manifestations of atomic bonding
production of materials
make them fast or slow to affect                properties
how a crystal-structure deformation is the basis of plastic deformation
edge dislocation
                 crystal structure
a            arrangement of atoms
in the middle, we have                  in an extra half-plane of atoms
compare to perfect crystal
contrast it with the dislocation area
if you draw a loop around it, you don't come back to the same place:                vector
Burgers vector
named after Dutch physicist Jan Burgers, is a vector, that represents the                    and direction of the lattice distortion resulting from a dislocation in a crystal lattice.
this is the basis of                        this structure in a mathematical way
the movement of those linear defects is the basis of plastic deformation
an object in the plastic deformation range will first have undergone elastic deformation, which is reversible, so the object will return part way to its                  shape
deformation
deformation refers to any changes in the shape or size of an object due to:
1. an applied           
2. a change in                       
as deformation occurs, internal inter-molecular forces arise that oppose the applied force
if the applied force is not too great, these forces may be sufficient to completely              the applied force and allow the object to assume a new equilibrium state and to return to its original state when the load is removed
elastic deformation
reversible
                     and shape memory metals
plastic deformation
irreversible
metal               
occurs primarily in ductile metals
was originally thought that a material deformed only within the elastic range returned completely to its original state once the forces were removed
however,              are introduced at the molecular level with each deformation
after many deformations,              will begin to appear, followed soon after by a fracture, with no apparent plastic deformation in between
The Six Categories of Engineering Materials
Dislocations Explain Plastic Deformation