Magnesium has become one of the most under consideration element in last few years because of its versatile application in engineering. its properties structure and alloys are most frequently used in engineering application

1. MAGNESIUM AND ITS ALLOYS
Moiz Ullah Baig (MM-036), Saad Arif (MM-026), Haris Iqbal (MM-020) & Omar Siddiqi (MM-004)
Materials Engineering Department
INTRODUCTION
The word ‘Magnesium’ is derived from the Greek
word ‘Magnesia’. It is a white silvery metal, dis-
covered by Joseph Black in 1755 at Edinburgh,
England. It is the 6th
most abundant element on
earth and about 2.4% of earth crust contains
magnesium.
PROPERTIES
Crystal
Structure:
Hexagonal
Closed Packed
Atomic Number: 12
Atomic Mass: 24.3
Configuration: [Ne] 3s2
Group: Alkaline Earth Metal
Melting Point:
651 °C
Boiling Point:
1100 °C
Density:
1.738 gm./cm3
Specific Gravity:
1.738
Burns in air with an intense white light,
produces a lot of heat.
Group:
II-A
Period:
III
APPLICATIONS
Aircraft parts
As desulfurizers
and deoxidizers
As anode in ship
hulls and ballast tanks
to protect from
corrosion
Automotive
parts
Bicycles and
sports goods
Laptops and
cellphones
Bohr’s Model
MAGNESIUM ALLOYS
Magnesium is the metal for the 21st
century. Mg-alloys are being considered as one of the
most versatile material choices amongst the structural materials that exhibit both energy
efficiency and environmental benefits. Mg-based materials (alloys and composites) have
enormous and unlimited potential to replace aluminum, steel and structural plastics in
diverse industrial and commercial sectors. Magnesium alloys have a relatively high
strength-to-weight ratio, with some commercial alloys attaining strengths as high as 380
MPa. High energy absorption means good damping of noise and vibration, as well as
impact and dent resistance.
Mg– Zn Binary
Alloy
Mg-Al Binary
Alloy
Zinc renders
more solid solution
strengthening than an equal
atomic percent of other alloying
elements. They have a
strong age hardening
response. By these
advantages, high
strength alloys
can be developed.
EFFECT OF
ZIRCONIA
The addition of
Zirconia (Zr)
enhances the
homogeneity of
microstructure by
making grains round. As a
result more zinc can dissolve
and contribute positively
to the strength of
alloy.
Solubility: 6.2% at eutectic temperature i.e. 341 °C
Solubility: 12.6% at eutectic temperature i.e. 437 °C
It is one of
the oldest and most
commonly used alloys.
Addition of aluminum reduces
the grain sizes and makes
dendrites finer and more
developed. Aluminum
increase hardness,
strength and has
minor effect on
density.
EFFECT OF
STRONTIUM
The effects of
strontium (Sr) on
microstructure are
found to be very
apparent. Addition of Sr
makes lamellar structure which
are distributedalongthegrain
boundaries and make
bettercreepresistant
alloy.
JOINING OF ALLOYS
Magnesium and magnesium alloys may be joined
by most of the common fusion and mechanical
fastening methods. Fusion methods include,
 Shielded-metal arc welding
 Gas welding
 Electric resistance seam and spot welding.
While mechanical fastening methods include,
 Riveting
 Bolting
 Adhesive bonding.
ADVANTAGES
DISADVANTAGES
 Good machinability
 Good creep resistance to 120 °C
 High thermal conductivity
 Easily gas-shield arc-welded
 High tendency to galvanic corrosion when
contact with dissimilar metals and electrolyte.
 Difficult to deform by cold working
 High Cost
REFERENCES
 Introduction to Physical Metallurgy 2nd Edition—Sidney H Avner
 Materials and Process in Manufacturing 10th
Edition—Paul DeGarrmo
 http://www.totalmateria.com/Article78.htm
 http://www.intlmag.org/magnesiumapps/overview.cfm
 https://www.forging.org/design/47-magnesium-alloys
 http://www.rsc.org/periodic-table/element/12/magnesium
 http://www.hindawi.com/journals/jma/2014/704283
 https://www.jstage.jst.go.jp/article/matertrans/49/6/49_MOV2007315
 http://www.foundryworld.com/uploadfile/20094161419781
 http://ir.lib.uwo.ca/etd/816/
 https://researchspace.auckland.ac.nz/handle/2292/22223
Magnesium
alloys are in use
around the world
in a variety of
different applications.
It is preferred
material when
looking for weight
reduction without
compromising
overall
strength.