alloys Flashcards
what are alloys
a combination of two or more metals
or a metal with a metalloid
Benefits of alloys
improved properties
o EL
o FS
o UTS
o Hardness
o More resistant to corrosion
o Lower melting point than individual metal
uses of alloys
steel
burs and instruments
gold alloy
inlays and crowns etc
cobalt chromium
dentures
nickel titanium
ortho wires
nickel chromium
crowns and bridge
amalgam
restoration
phase definition
Physically distinct homogenous structure
Can have more than one component
solution definition
Homogenous mixture at an atomic scale
pure metal has how many phases
1
an alloy with 2 insoluble metals has how many phases
2 phases
solid solution has how many phases
1
solid solution def
2 metals coexisting in a lattice network; both metals in a homogenous mixture
3 categories of alloys
- 2 phases (insoluble)
- intermetallic compound (partially soluble)
- 1 phase (solid solution)
solid solution has 3 types what r they
- substitutional random
- substitutional ordered
- interstitial
diff between cooling curve of metal and alloy?
pure metal Crystalises at one temperature
alloy Crystallizes over a range of temperatures (between TL and Ts)
liquidus def
line representing the temperature which different alloy composition begin to crystallise
solidus def
line representing the temperature which different alloy composition have completely crystallised
do you want fast or slow cooling
fast