Hierarchy of Iron Alloys
Feb 18, 2016
Hierarchy of Iron Alloys
Numbering System
Low Carbon Steel
Medium Carbon Steel and its Alloys
With a small amount of Si, Fe3C → -Fe and graphite
Cast Iron
Clockwise from upper left: gray cast iron, nodular (ductile) cast iron, white iron and malleable iron
Stainless Steels
Tool Steels
Aluminum Alloys
Copper Alloys
Titanium Alloys
Magnesium Alloys
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• Properties: --Tmelt for glass is moderate, but large for other ceramics. --Small toughness, ductility; large moduli & creep resist.• Applications: --High T, wear resistant, novel uses from charge neutrality.• Fabrication --some glasses can be easily formed --other ceramics can not be formed or cast.
Glasses Clay products
Refractories Abrasives Cements Advanced ceramics
-optical -composite reinforce -containers/ -household
-whiteware -bricks
-bricks for high T (furnaces)
-sandpaper -cutting -polishing
-composites -structural
engine -rotors -valves -bearings
-sensors
TAXONOMY OF CERAMICS
• Need a material to use in high temperature furnaces.• Consider Silica (SiO2) - Alumina (Al2O3) system.• Phase diagram shows: mullite, alumina, and crystobalite (made up of SiO2) tetrahedra as candidate refractories.
6Composition (wt% alumina)
T(°C)
1400
1600
1800
2000
2200
20 40 60 80 1000
alumina +
mullite
mullite + L
mulliteLiquid (L)
mullite + crystobalite
crystobalite + L
alumina + L
3Al2O3-2SiO2
APPLICATION: REFRACTORIES
tensile forceAo
Addie
die
• Die blanks: --Need wear resistant properties!
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• Die surface: --4 m polycrystalline diamond particles that are sintered on to a cemented tungsten carbide substrate. --polycrystalline diamond helps control fracture and gives uniform hardness in all directions.
APPLICATION: DIE BLANKS
• Steels: increase TS, hardness (and cost) by adding-C (low alloy steels)-Cr, V, Ni, Mo, W (high alloy steels)-Ductility usually decreases w/ additions
• Nonferrous:-Cu, Al, Ti, Mg Refractory, and noble metals
• Basic categories of ceramics:-Glasses-Clay products-Refactories-Cements-Advanced ceramics
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SUMMARY