ALLOYS Flashcards
WHAT ARE MONELS?
Nickel alloyed with primarily copper.
WHAT ARE INCONELS?
Nickel alloyed with primarily chromium
WHAT ARE INCOLOYS?
Iron based with 9–49% nickel, chromium.
WHAT ARE HASTELOYS?
Nickel alloyed with Iron, Chromium and Molybdenum.
WHY ARE NICKEL AND NICKEL ALLOYS VITALLY IMPORTANT TO MODERN INDUSTRY?
DUE TO THEIR ABILITY TO WITHSTAND A VARIETY OF SEVER OPERATING CONDITIONS INCLUDING:
- corrosive environments
- high temperatures
- high stresses
- combinations of above factors
WHAT ARE SOME COMMON CHARACTERISTICS OF NICKEL?
1) Good toughness and ductility
2) Good high and low temperature strength
3) Can be work hardened to improve strength and hardness
4) Alloying allows for precipitation hardening ( Al, Ti, Si, Mg)
5) Very High Cost
6) Good Corrosion Resistance
7) Pure Nickel is slightly magnetic, alloyed nickel is not
8) Light Grey in color
9) Weldable
WHAT IS 80% OF COPPER USED FOR IN THE WORLD?
PLUMBING SYSTEMS
WHAT ARE SOME COMMON CHARACTERISTICS OF COPPER?
1) High electrical conductivity – second only to silver
2) High thermal conductivity – again, only second to silver
3) Good corrosion resistance
4) Good fatigue resistance
5) Reasonable tensile strength – (150 – 450 MPa)
6) Can be alloyed to improve strength
7) Can be cold worked to improve strength
8) Non-magnetic
9) Reddish-brown, golden, silvery depending upon alloying elements added
10) Good soldering joining characteristics, some highly alloyed ones can be welded.
WHAT IS NATURAL ALUMINUM CALLED IN ITS COMPLEX MIXTURE OF MATERIALS THAT CONTAINS MOSTLY ALUMINUM HYDROXIDE?
BAUXITE
WHAT ARE THE 2 STEPS IN THE PROCESS OF RETRIEVING ALUMINUM?
- BAYER PROCESS
- HALL-HEROULT PROCESS
WHAT IS THE BAYER PROCESS?
Using caustic leaching, alumina (Al2O3) is produced. It comes
off as affine white powder when the fluids are evaporated off
WHAT IS THE HALL-HEROULT PROCESS?
Uses Electrometallurgy to further separate the
Aluminum and oxygen. A mineral Cryolite Na3AlF6) is introduced along with an electric
current creating an electrolytic cell. The Aluminum melts – settles, and is tapped off the
bottom of the bed.
WHAT ARE SOME ADVANTAGES OF USING ALUMINUM?
1) Light (about 1/3 the density of steel)
2) Good thermal and electrical conductivity
3) High strength to weight ratio
4) It increases in tensile strength as the temperature decreases (only metal to do this
making it ideal for cryogenic applications)
5) Most aluminums are weldable
6) Good atmospheric corrosion resistance due to the Aluminum Oxide layer
7) Non-magnetic
8) Good formability (malleable)
9) Non-toxic
WHAT IS THE HEAT TREATMENT USED TO STRENGTHEN ALUMINUM CALLED?
PRECIPITATION HARDENING
PRECIPITATION HARDENING (USED FOR HEAT TREATING ALUMINUM) HAS 3 STEPS. WHAT ARE THEY?
- SOLUTION HEAT TREATING (SOLUTIONIZING)
- QUENCHING
- AGING - NATURAL OR ARTIFICIAL
WHAT IS ARTIFICIAL AGING?
age at an elevated temperature to precipitate the secondary
phase quicker and to optimize the strength that can be achieved. Care must be taken that over aging does not occur.
