Solutions
2000 Correct Ans--copper is major alloying element
-copper gives strength
-heat treatable
-not good food corrosion resistance
-artificial/furnace aging (T6)
-heat treated condition: mechanical properties close or even exceed mild steel
-2024 is best known alloy
3000 Correct Ans--Manganese is major alloying element
-non-heat treatable
-good strength
-limited: won't absorb > 1.5% Mn
-good workability
-3003 - general purpose alloy
4000 Correct Ans--Silicon is major alloying element
-dark gray when anodizing
-Si lowers melting point without causing brittleness
-used in welding wire and brazing alloys
,-non-heat treatable
5000 Correct Ans--magnesium is major alloying element
-good weld characteristics
-problems with stress corrosion cracking at higher temperatures
-resistance to marine atmosphere corrosion
-most effective and widely used alloy
-non-heat treatable
-moderate to high strength
6000 Correct Ans--magnesium and silicon are major alloying elements
-forms magnesium silicide
-not as strong as 2000 or 7000
-corrosion resistance
-6061 most used (T6)
-heat treatable
-good formability
7000 Correct Ans-Zinc is major alloying element
-Heat treatable
-high strength
-no arc weld- tends to crack
, -lighter and stronger (aircraft)
heat treatable aluminum series Correct Ans-2000s 6000s 7000s
non-heat treatable aluminum series Correct Ans-1000s 3000s 4000s 5000s
-cannot make harder
-can try using cold work (strain hardening)
Suffix XXXX - HXX Correct Ans-H- deals with strain hardening
H1X-strain hardened only
H2X-strain hardened and partially annealed
H3X-strain hardened and stabilized by low-temp. thermal treatments
-the second number represents the degree of strain hardening: X/8 (out of 8)
HX1-least hard
HX8-max hard
precipitation hardening Correct Ans--no phase change
-limited solubility
-heated, water quenched then aged
aging Correct Ans--develops precipitates
-heat makes it faster