Metallic glasses are metal alloys that are amorphous, meaning they lack long-range atomic order and have a glass-like structure. They can be produced through rapid cooling techniques that solidify the molten metal before crystallization occurs. Metallic glasses have strong, corrosion-resistant, and homogeneous properties due to their amorphous structure. They also exhibit a reversible glass-liquid transition when heated instead of melting. Potential applications of metallic glasses include use in transformer cores, sensors, surgical instruments, and electronic devices due to their electrical and magnetic properties.

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3. Metallic glasses are the newly developed engineering materials.
Metallic glasses share the properties of both metals and alloys.
Most metals and alloys are crystaline,i.e., their atoms arranged in
some regular pattern that extends over a long distance.
In contrast,glass is an amorphous,brittle and transparent solid.
Thus,metallic glasses are metal alloys that are amorphous.

4. The major advantages of such glasses are that they are generally
homogeneous in composition,and offer strong and superior
corrosion resistance.
To have this perculiar property,metallic glasses are to be made by
cooling a molten metal rapidly at a rate .
Thus,the liquid reaching the glass transition temperature Tg
solidifies as metallic glass.Again, upon heating, metallic glasses
show a reversible glass-liquid transition at Tg.
that is, they do not have a long range atomic order.

5. Various rapid cooling techniques such as spraying,spinning
and laser deposition are used for the production of metallic
glasses.
The melt spinning process technique involved in the
preparation of metallic glass is illustrated in figure.
In this technique,there is a spinning
disc made of copper. In order to
prepare a metallic glass of a particular
type, a suitable combination of metal-
metal or metal-metalloid alloy in bits
stoichiometric ratio is taken in a
refractory tube having a fine nozzle at
its bottom.The nozzle side of the tube
is placed just over the spinning disc.
PREPARATION

6. An induction heater attached to the refractory tube melts the
alloy. This melt is kept above its melting point till it gets
transformed into a homogeneous mixture. An inert gas such as
helium is made to flow through the tube containing the
homogeneous mixture. As a result the melt gets ejected through
the nozzle. The ejected melt is cooled at a faster rate with the
help of the spinnig cooled copper disc. The ejection rate can be
increased by increasing the pressure of the inert gas. Thus,a
glassy alloy ribbon satrts getting formed over the spinning disc.
The thickness of the glassy ribbon may be varied by increasing or
decreasing thr speed of the spinnig disc.

7. 1. The strength of metallic glasses is very high but they are lighter in
weight.
2. They are ductile,malleable,brittle and opaque.The hardness is very
high.
3. The toughness is very high,i.e.,the fracture resistant is very high.
4. They have high elasticity,i.e.,the yield strength is high.
5. They have high corrosion resistance.
6. They do not contain any crystalline defects like point
defects,dislocation,stacking faults,etc.
7. They are soft magnetic materials.As a result,easy magnetisation and
demagnetisation are possible.
8. They have high electrical resistivity which leads to a low eddy
current loss.
PROPERTIES OF METALLIC GLASSES:-

8. 1. Metallic glasses are used as transformer core material in high-
power transformers.Usage of metallic glasses in transformers is
found to improve the efficiency of power distribution in
transformers.These transformers are used to convert high-voltage
current into low-voltage current to be used for domestic
appliances(120 V and 240V).
2. Because of their high electrical resistivity and nearly zero
temperature coefficient of resistance,these materials are used in
making cryothermometers,magnetoresistance sensors and
computer memories.
3. As the magnetic properties of the metallic glasses are not affected
by irradiation they are used in making containers for nuclear waste
disposal.
4. These materials are used in the preparation of magnates for fusion
reactors and magnets for levitated trains,etc.
APPLICATONS:-

9. 1. Metallic glasses can also be used for making watch cases to replace
Ni and other metals which can cause allergic reactions.
2. The excellent corrosion resistance property makes these materials
ideal for cutting and in making surgical instruments. In
addition,they can be used as a prosthetic material for implantation
in the human body.
3. In future, the usage of metallic glasses in the electronic field can
yield stronger,lighter and more easily moulded castings for personal
electronic products.
4. Metallic glasses are used in tap reorders as heads,in the
manufacture of sprongs and standard resistances.

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