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Notes on video lecture:
Dislocations Explain Plastic Deformation
Notes taken by Edward Tanguay on January 17, 2016 (go to class or lectures)
Choose from these words to fill the blanks below:
desired, stiffness, original, cubic, cracks, magnitude, force, metallic, microscopic, temperature, resist, ceramics, faults, fatigue, Burgers, macroscopic, quantifying, carbon, elastomers, semiconductors, squeezed, properties
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six materials that engineers have to work with:
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1. metals
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2. polymers
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3.                 
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4. glass
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5. fiberglass
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6.                             
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in each case there is a difference at a very low level
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e.g. in the case of fiberglass, the                        architecture of the fiber-reinforced composite
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underlying principle
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a mantra of material science: structure leads to                     
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differences at the atomic or microscope level lead to differences at the                        or engineering level
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stress-strained curve
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early concept of atomic bonding led to characteristic of                   
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bonding force curve is the first derivative of the bonding energy curve
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two              atoms in a polymer
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two aluminum atoms in a aluminum alloy
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the difference between an aluminum and oxygen ion in an aluminum oxide
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at the atomic scale, we are trying to tear atoms apart
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a macroscopic scale manifestations of atomic bonding
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production of materials
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make them fast or slow to affect                properties
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how a crystal-structure deformation is the basis of plastic deformation
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edge dislocation
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                 crystal structure
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a            arrangement of atoms
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in the middle, we have                  in an extra half-plane of atoms
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compare to perfect crystal
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contrast it with the dislocation area
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if you draw a loop around it, you don't come back to the same place:                vector
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Burgers vector
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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.
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this is the basis of                        this structure in a mathematical way
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the movement of those linear defects is the basis of plastic deformation
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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
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deformation
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deformation refers to any changes in the shape or size of an object due to:
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1. an applied           
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2. a change in                       
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as deformation occurs, internal inter-molecular forces arise that oppose the applied force
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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
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elastic deformation
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reversible
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                     and shape memory metals
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plastic deformation
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irreversible
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metal               
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occurs primarily in ductile metals
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was originally thought that a material deformed only within the elastic range returned completely to its original state once the forces were removed
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however,              are introduced at the molecular level with each deformation
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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