Solid solution diagrams and Eutectic diagrams Flashcards
Basics of solid solutions
What is a solid solution?
Formed when materials which are dissolved in each other in the liquid state and remain so in the solid state
What is the region between two phases?
A two phase region, where both can exist; similar to triple point
What is the liquidus line?
Line where anything above is liquid
What is the solidus line?
Line where anything above is solid
What is a substitutional solid solution?
Solute can substitute into lattice and replace solvent (why alloying is easy); typically solvent and solute atoms are similar size
What is an interstitial solid solution?
Solute insert themselves into lattice; typically solvent and solute atoms are different size
What is the implications of different sized solute and solvent atoms?
Work hardening caused by larger solvent atoms falling in and create tension, preventing dislocations from moving
What is the lever rule for?
To find compositions within the two phase region
What is the lever rule for finding liquid composition?
Tie line to liquidus line, and drop line to find %
What is the lever rule for finding solid composition?
Tie line to solidus line, and drop line to find %
What happens when two metals are mixed (in a eutectic diagram?
Melting point decreases until eutectic point
What is the eutectic point?
Where both metals melt; lowest melting point
What are alloys of composition to the left of the eutectic point called?
Hypoeutectic
What are alloys of composition to the right of the eutectic point called?
Hypereutectic
What are alloys of composition of the eutectic point called?
Eutectic
