# Shared Flashcard Set

## Details

Chapter 5
MSE 2001
23
Other
04/24/2016

Term
 Edge dislocation line moves ___ to applied stress.Screw dislocation line moves ___ to applied stress.
Definition
 ParallelPerpendicular
Term
 Geometric slip plane
Definition
 The plane of the dislocation
Term
 Crystallographic slip plane
Definition
 The highest atomic density plane
Term
 Burgers vector connects...
Definition
 The atoms of closest approach
Term
 What 2 assumptions must Burger's Vector meet in order to be chosen?
Definition
 1. Connects lattice points (equivalent lattice positions)2. Shortest vector
Term
 Twin boundaries
Definition
 Reflections across a mirror plane to generate the structure
Term
 Decreasing the grain size, _____ the strength.
Definition
 Increases
Term
 In edge dislocation, Burgers vector is _____ to dislocation line.In screw dislocation, Burgers vetor is _____ to dislocation line.
Definition
 PerpendicularParallel
Term
 Impeding the motion of dislocations, _____ the strength
Definition
 Increases
Term
 Dislocations allow plastic deformation to occur at ____ stresses than if they were not present
Definition
 Lower
Term
 4 ways to impede motion of dislocations / increase strength
Definition
 1. Addition of impurities / solute / alloying2. Increase dislocation density / strain hardening3. Decrease grain size / grain refinement decrease4. Presence of volume / precipitation / precipitation hardening
Term
 Climb
Definition
 The motion of an edge dislocation that occurs when vacancies migrate to the extra half plane of atoms
Term
 The probability of a dislocation climb _____ as temperature increases.
Definition
 Increases
Term
 Are dislocations thermodynamic defects?
Definition
 NO
Term
 Is a vacancy a thermodynamic defect?
Definition
 YES
Term
 Edge dislocation
Definition
 A dislocation that is formed by the insertion of an extra half plane into an otherwise perfect region of a crystal.
Term
 Why is there a tension and compressive side of a dislocation?
Definition
 Because where the dislocation is inserted, the side with the fewer amount of atoms has tension to spread its area further out. Then the side with more atoms, tries to compress its area to fit the smaller side.
Term
 Why do edge dislocations tend to form symmetric tilt boundaries?
Definition
 Because the edge dislocations act as a wedge that tilts the two halves of the grain about an axis that lies in the plane of the boundary.
Term
 The energy of a dislocation is proportional to ______.
Definition
 Square of Burgers Vector
Term
 Simply, how do you strengthen a metal?
Definition
 By impeding the dislocation motion.
Term
 How does plastic deformation occur, with regards to dislocation?
Definition
 By dislocation motion
Term
 To make material more ductile, do you add or remove dislocation lines?
Definition