Metal Defects (Leaving Cert Engineering): Flashcards
📚Flashcards
Practise the cards
12 cards from this deck
ShowHide
Practise the cards
12 cards from this deck
What are line defects?
What are line defects?
Structural imperfections that occur along a line within a crystal lattice
What dimension are line defects?
What dimension are line defects?
One-dimensional imperfections
What is a dislocation?
What is a dislocation?
Most common type of line defect in crystalline materials
What is the structure of a dislocation?
What is the structure of a dislocation?
Incomplete row of atoms within crystal structure
What makes dislocations mobile?
What makes dislocations mobile?
Shear stress applied to the material
Where do dislocations travel under stress?
Where do dislocations travel under stress?
From interior towards surface of material
What forms when a dislocation reaches the surface?
What forms when a dislocation reaches the surface?
A crack (crack initiation point)
What does an incomplete row of atoms create?
What does an incomplete row of atoms create?
Areas of high stress (stress concentration)
Why do dislocations move easily?
Why do dislocations move easily?
They represent the easiest path for atoms to rearrange
Energy needed: moving dislocation vs deforming perfect crystal?
Energy needed: moving dislocation vs deforming perfect crystal?
Less energy needed to move a dislocation
How do dislocations affect mechanical properties?
How do dislocations affect mechanical properties?
Make materials harder or more brittle than intended
What do moving dislocations create?
What do moving dislocations create?
Weaknesses and potential failure points