3. ● Great chemical stability
● Ease of machinability and fabrication
● Light weight
● Environmentally friendly
● 2/3rd the weight of aluminium alloys and
1/3rd the weight of iron and steel.
● Used for structural applications primarily
in aircraft and missile industries.
● High thermal conductivity,tensile
strength(228-290 MPa),heat
resistance(upto 450 deg),oxidation
resistance(upto 500 deg).
INTRODUCTION
4. ● 8th most abundant metal.
● 2% of earth’s crust
● Cheapest and lightest metal.
● 3rd most plentiful element dissolved in
seawater.
● Found in over 60 minerals,among them
dolomite,magnesite,brucite,carnallite &
olivine are commercially important.
● It forms alloys but use has been limited
by its tendency to corrode, creep at
high temperatures and combust.
CHARACTERISATION
OF BASE METAL
(Mg)
6. 1. Addition of aluminium increases hardness and strength,reduces
ductility
2. If Al % is greater than 13,the material becomes too brittle.
3. Addition of Mn increases corrosion resistance.
4. To improve corrosion resistance under saline conditions 1-2%Zn is
added.
5. Zirconium refines grain size in sand and gravity castings (not
combined with aluminum)
6. Tin improves castability.
7. Aluminium,zinc,zirconium and thorium promote precipitation
hardening.
8. Copper increases both room and high temperature strength.
ALLOYING EFFECTS
7. NOMENCLATURE
● The most common designation of
magnesium alloys is based on ASTM
publication.
● The first two letters of ASTM
nomenclature indicate principal alloying
elements.
● A-aluminium;B-bismuth;C-copper;D-
cadmium,E-rare earths;F-iron;G-
magnesium,H-thorium;K-zirconium;L-
lithium;M-manganese;N-nickel;P-lead;Q-
silver;R-chromium,S-silicon,T-tin,Y-
antimony,Z-zinc
● The two alloying elements are arranged in
order of decreasing percentage,or in
alphabetical order if of equal percentages
followed by respective percentages
rounded off to whole numbers.
11. Magnesium, Aluminium and Zinc
● Common type of heat treatable alloy
● Artificial or natural aging causes increase in yield
strength
● Ductility of the alloy decreases due to heat treatment
● Lightweight and highly corrosion resistant
● It is manufactured in various ratios
● E.g.-High Mg(e.g.-93%Mg 6%Al%1Zn-AZ61A),
similarly high Al, high Zn
12. ● Small amounts of Zirconium, manganese and chromium
may be added to obtain fine grain structure before heat
treatment.
● Corrosion resistance is good in the alloys containing
small amount of copper.
● Used in various aircraft structures
Forging, extrusions, sheets.
● Manufacturing hydraulic equipments
13. Magnesium, Zinc, Rare earth(Re) and Zirconium Alloys
● Most widely used alloys for sand casting
● Rare earth is added to improve castability
● Complex castings can be made with virtually no
microporosity
● Retains mechanical properties upto temperature of
150℃
● Used in gear box casting, jet engines, etc.
14. Magnesium, Zirconium Alloys containing Silver
● Improved high temperature (200℃) properties
compared to Mg-Zn-Rare earth-Zr alloy
● Silver is the main strengthening element
Common alloy contains 2.5% SILVER
● Rare earth elements added - neodymium,
praseodymium
● Uses - Aerospace gearbox, engine casings requiring
high temperature performance.
15. Magnesium, Zirconium Alloys containing Yitrium
● Improved mechanical properties at high temperature
compared to other magnesium alloys
● Considered as alternative to thorium containing alloys
● Very high resistance to corrosion than other
magnesium alloys
● Uses - Alternative to Al alloys in racing cars for large
engine casting
● Many applications in aerospace industry due to its
combination of strength ductility and corrosion
resistance.
16. ELEKTRON (ELEKTRONMETALL)
● One of the most famous alloys of Magnesium.
● British company Magnesium Elektron Ltd.
● 0% to 9.5% alloying elements.
● Composition:
Aluminium(<9.5%), Yttrium(5.25%), Neodymium(2.7%),
Silver(2.5%), Gadolinium(1.3%), Zinc(0.9%), Zirconium(0.6%),
Manganese(0.5%) and other rare earth elements
● Varying composition - variations in properties.
17. ELEKTRON (ELEKTRONMETALL)
● One of the most famous alloys of Magnesium.
● British company Magnesium Elektron Ltd.
● 0% to 9.5% alloying elements.
● Composition:
Aluminium(<9.5%), Yttrium(5.25%), Neodymium(2.7%),
Silver(2.5%), Gadolinium(1.3%), Zinc(0.9%), Zirconium(0.6%),
Manganese(0.5%) and other rare earth elements
● Varying composition - variations in properties.
18. ● Unusually light(Specific gravity of about 1.8).
● Good castability because of low oxidation properties.
● Due to relatively low density of Magnesium, these alloy
variants have different aircraft and motor racing
applications.
19. MAGNOX
● Mainly composed of Magnesium and small amounts of
Aluminium.
● Abbreviation for Magnesium non-oxidising.
● It has many industrial applications.
20. ● Magnox is used in cladding unenriched Uranium metal
fuel to contain fission products in nuclear reactors.
● Low neutron capture cross section.
● Limits the maximum temperature of the plant to 360 C.
● Reacts with water, preventing the long term storage of
fuel.
21. MAG-THOR
● Common name for range of Magnesium alloys containing
Thorium.
● Also contains Manganese and Zinc.
● Names are given by two letters followed by two numbers.
e.g.,HM31 - 3% Thorium and 1% Manganese
● Light weight
● High strength
● High creep resistance(upto 350 C)
22. ● Low melting point.
● Rapid oxidation.
● Several aerospace applications.
● Was used in engine construction of missiles and drones.
(e.g.,Bomarc missile)
● But, no longer used due to radioactivity of Thorium.
23. Metal 12
● Alloy of magnesium and aluminium
● Developed by samsung in 2018
● Lightweight and durable
● Magnesium is lighter than aluminium and stronger per
unit volume at the same time
● Thus magnesium is also termed as metal of the future
