Metals and Alloys Flashcards
What effect does rapid cooling have on metals and alloys?
Forms more nuclei per unit volume and decreases the grain size
What does ductility and malleability mean?
The ability of atomic centers to slide against each other into new positions within the same crystal lattice
How does finer grain size affect metals and alloys?
Can raise the yield strength, increase the ductility, and raise the ultimate strength
Why would a material fracture?
B/c a crack opens up on a grain boundary
When is a fracture more likely to occur in metals and alloys?
In large grain metals when the planes can not be slipped into the adjacent grains
Changes of what properties with grain size are related to plastic deformation and fracture?
Yield strength, ductility, and ultimate strength
What is the mechanism of plastic deformation called?
Dislocation motion
What are dislocations?
Flaws in the crystal that allows atomic centers to slide past each other one plane at a time instead of forcing all planes to be overcome simultaneously
What is cold working (wrought)?
Causing plastic deformations by hammering, drawing, cold forging, cold rolling or bending.
What does cold working produce?
Many dislocations that can not slip easily thru each other as the lattice becomes more distorted
What happens to grains in cold working?
They are broken down and entangled in each other.
What kind of metal has a melting range? Melting point?
Metal alloy.
Pure metal has a melting point
The areas between a liquid and a solid alloy on graph is referred to as what?
Melting range
What are the three things that you can get from an alloy that is heated and cooled down?
Soluble - solid solution
Not soluble - eutectic
Sometimes the elements react to form an intermetallic compoung
When metals are mixed together in a molten state and cooled - what does the result depend on?
The solubility of the metals in each other
