good morning friends today let us learn about
copper zinc and titanium cast alloys copper
zinc and titanium cast alloys
so first we will see the copper cast alloys
now the characteristics of copper what are
the characteristics of copper one is high
electrical conductivity that we know very
well next one high thermal conductivity next
one high corrosion resistance good ductility
and malleability next one reasonable tensile
strength and finally it is non toxic so these
are the characteristics of copper you can
see on our favourable characteristics thats
why there is a lot of demand for copper in
the industry not only the industry for the
domestic applications
these are the physical properties of copper
crystal structure is f c c face centred cubic
system atomic number is twenty nine atomic
weight is sixty three point five density eight
point nine grams per c c melting point is
thousand and eighty four point six centigrade
now this is the way the copper alloys have
been developed with the different objectives
now you can see here there are what say five
objectives are there one is to an object to
were strength has to be increased and another
objective could be increase of the corrosion
resistance or another objective could be increase
of wear resistance or another objective could
be increase of the machinability next one
increase in the colour
so what is your objective besides the development
of the copper alloy if you are objective is
to enhance the strength of the alloy then
these alloying elements are to be added like
phosphorus zinc zirconium chromium iron aluminium
silicon nickel manganese beryllium and so
on and if your objective is to increase the
corrosion resistance then we have to add these
elements like nickel aluminium tin manganese
iron silicon arsenic and so on and if your
objective is to increase the wear resistance
of an alloy then these elements have to be
added like aluminium tin cadmium silicon silver
and so on and if the objective is to increase
the machinibility of the copper alloy then
these elements are to be added lead zinc sulphur
and so on and if your objective is to increase
the colour then these are the elements zinc
tin nickel and so on
so based on the objective or the purpose or
the application different alloy alloying elements
are added to the copper and the copper alloying
is developed now this is the classification
of the copper alloys first classification
is according to the chemical composition and
the second composition is according to the
application first let us see the classification
according to the chemical composition under
that we have unalloyed copper next one we
have brasses brass means copper and zinc and
other alloying elements next one bronzes means
copper tin and other alloying elements except
zinc cupronickle that is copper and nickel
alloy and here you can see brass means you
can see copper is the base element and zinc
is the main and the primary alloying element
and in the bronze copper is the base element
and tin is the primary alloying elements and
it wont ah though other elements are present
yes but zinc wont be present
and next classification is according to the
application they can be classified as cast
alloys and wrought alloys now let us see the
unalloyed copper these are the characterises
of the unalloyed copper one is good electrical
and thermal conductivities next one high corrosion
resistance easily fabricated reasonable tensile
strength controllable annealing properties
good soldering and joining properties
now you see these are the typical applications
of the unalloyed copper and you can see here
this is the copper finished parts copper trolley
wires electronic products copper heat sink
so in all these cases we use the unalloyed
copper
next one under the what say chemical composition
we have another one is the brass brass means
copper zinc and other alloying elements will
be there but zinc is the primary alloying
element brass now brass is an alloy ah alloy
primarily made up of copper and zinc although
copper and zinc form the basis of any brass
aluminium lead and arsenic are often used
as alloying agents to improve machinability
and corrosion resistance brass alloys can
be made using a variety of compositions in
order to meet the exact demands of a given
application
now these are the typical applications decorative
items for its bright gold like appearance
applications where low friction is required
such as locks gears bearings doorknobs ammunition
casings and valves next one plumbing and electrical
applications next one musical instruments
such as horns and bells for acoustic properties
so these are all the typical applications
of the brass
now we can see more applications this is this
is a decorative lamp stand you see this is
made up of brass now this is a brass boat
propeller so this is also made up of brass
now this is a brass sampling cock and you
can see here so this is also a brass alloy
component
now let us see the effects of alloying elements
in brasses so what happens when we add different
alloying elements first one is lead lead is
added up to three percent to improve the machinability
so this greatly improves the machinability
it appears as a dispersed discontinuous phase
distributed throughout the alloy so the next
alloying element is tin about one percent
of tin is included in some brasses to provide
improved corrosion resistance so tin improves
is the corrosion resistance the next alloying
element that appears in the brass is the silicon
silicon increases the strength and wear resistance
of brass it also reduces oxidation of the
zinc and improves the fluidity of the alloyed
so wherever silicon comes into picture it
improves the fluidity next one other elements
next one is the arsenic arsenic is often added
in small amounts to alpha brass alloys to
provide protection against dezincification
corrosion next one is the nickel silvers the
copper nickel zinc alloys containing from
ten to twenty percent nickel also known as
nickel silvers they have a silver appearance
rather than the typical brassy colour in most
respects they show superior corrosion resistance
characteristics
next let us see the different types of brasses
one is the gilding metal where the zinc content
is less than five percent next one is commercial
brass where the zinc content is less than
ten percent or approximately ten percent next
one is jewellery brass in this case we have
zinc around twelve point five percent next
one we have the red brass in this case we
have zinc around fifteen percent next one
we have the low brass in this case the zinc
content is around twenty percent next one
we have the cartridge brass in this case the
zinc content is around thirty percent next
one is yellow brass in this case the zinc
content is around thirty five percent next
one muntz metal where the zinc content is
around forty percent
now these are the typical applications of
the brass and you can see a safety clamp for
high voltage systems made up of low brass
this is a brass cartridge now flange made
up of yellow brass
next let us see the bronzes so far we have
completed unalloyed copper and brasses now
we will see the bronzes bronzes are principally
they principally contain copper and tin bronze
doesnt necessarily contain tin generally they
contain copper and tin of course copper is
the base element and tin is the primary alloying
element most of the cases a variety of co
alloys of copper including alloys with arsenic
phosphorus aluminium manganese and silicon
are commonly termed as bronze phosphorus is
usually added as a deoxidizing agent called
phosphor bronzes copper tin confirm solid
solution up to fifteen point eight percent
at about five hundred and twenty to five hundred
and eighty six degrees centigrade
now let us see the different types of bronzes
tin bronzes so that is copper tin solubility
is fifteen point eight percent tin next one
aluminium bronze where there will be nine
point eight aluminium and ten percent that
is about ten percent aluminium next one silicon
bronze it is five point three percent silicon
beryllium bronze will be there next one phosphorus
bronze and lead branch and here you can see
this is a bronze gear a high pressures flange
for your sub sea weapon system made up of
aluminium bronze its a very what says typical
component of the branch and silicon bronze
for door fittings phosphor bronze cables
so with this we are completing the bronzes
ah finally we will come to the cupronickel
c u nick c u n i what is this cupronickel
cupronickel or copper nickel is an alloy of
copper that contains nickel and strengthening
elements such as iron and manganese cupronickel
is highly resistant to corrosion especially
in sea water now what are the applications
of cupronickel piping in sea water heat exchangers
condensers in sea water systems marine hardware
propellers and crankshafts of tugboats fishing
boats and other working boats strings for
string instruments and so on
so these are the important applications of
the cupronickel other applications of cupronickel
silver coloured modern coins seventy five
percent of copper and twenty five percent
of nickel and a trace amount of manganese
thermocouples and resistors fifty five percent
of copper forty five percent of nickel alloy
constantan and in the beginning of the twentieth
century bullet jockets were commonly made
from this material currently cupronickel remains
the basic material for silver plated cutlery
and this is commonly used for mechanical electrical
and medical equipments zippers jewellery items
and so on so this are the cupronickel cutlery
cupronickel flange so with this we are completing
the a copper alloys next let us see the zinc
cast alloys now what are the characteristics
of zinc alloys it has got no melting point
good corrosion resistance good fluidity fast
rate of die casting and moderate strength
this is the classification of the zinc alloys
broadly they can be classified as zinc cast
alloys and zinc wrought alloys now we will
be concentrating all these zinc cast alloys
so they can be classified into further into
two types one is the conventional zinc cast
alloys and zinc aluminium cast alloys so first
let us see the conventional zinc cast alloys
conventional zinc cast alloys are based on
zinc and four percent aluminium and zinc eight
percent aluminium aluminium can form solid
solution with zinc at what say low quantity
at three eighty two degree centigrade and
gives eutectic reaction at five percent aluminium
now these are the characteristics of the zinc
cast alloys high castability easy finishing
good mechanical properties free from intergranular
corrosion now let us see this is the aluminium
zinc face diagram now you see here so say
this is the zinc what say hundred percent
zinc and at this point you see may be ah ten
per ah ninety percent zinc and ten percent
aluminium
here we can see an eutectic reaction means
they reaction where having the lowest melting
point and here you can see this is the ah
may be this is three hundred and eighty two
degree centigrade role of alloying elements
in conventional zinc cast alloys aluminium
is added for strengthening reducing grain
size improving fluidity and minimising the
attack of the molten zinc alloy on the iron
next one magnesium is added in a small amount
you see this amount point zero one to point
three to prevent intergranular corrosion due
to the presence of lead cadmium and tin impurities
but excessive amount of magnesium lowers the
fluidity and promotes hot cracking next one
copper minimises effect of impurities improves
improve strength and hardness copper should
be less than one percent higher amounts of
what say copper leads to toughness and embrittlement
next one mechanical properties you see tensile
strength is between two hundred and twenty
two four hundred and forty mega pascal yield
strength two hundred and ten to three eighty
mega pascal and elongation is one to ten percent
next one let us see zinc aluminium z a casting
alloys z a casting alloys are z a eight z
a twelve and z a twenty seven alloys z and
a letters refer to zinc and aluminium respectively
and number refer to the percentage weight
of aluminium in each alloy small additions
of copper and magnesium give a good strength
stability and castibility characteristics
of zinc aluminium z a casting alloys they
have excellent machinability they have good
surface finish for decorative parts normally
is is first choice of replacing cast iron
brass and aluminium alloys applications of
zinc cast alloys die castings used for auto
mobile parts handles locks and so on used
for making body hardware light fittings instruments
and so on parts with thin walls and intricate
shapes several mechanical and electrical components
galvanic protection on steels decorative finish
on several components now this is a typical
component produced with the zinc alloy what
say alloy zinc alloy automotive engine block
you see
now this is the zinc alloy automotive mould
base zinc alloy automotive carburetor body
so this the carburetor body which is used
in the auto mobiles next one zinc alloy what
say products for automobile applications miscellaneous
applications next one typical z a twenty seven
products advantages of zinc alloys ability
of zinc to die cast at high productive rates
due to zincs relatively low melting point
so you see the melting point four hundred
and nineteen degree centigrade because of
that it is easy to cast them using die casting
process ability to produce near net shapes
of intricate designs with close dimensional
tolerance and good surface finishes zinc die
castings can be machined bent swaged riveted
welded and soldered relatively good atmospheric
corrosion resistance especially in what say
chromium solution forming surface protective
film surface what say sufficient strength
for some applications and finally economical
compared to aluminium and copper alloys (( )) next
we will see the disadvantages of copp zinc
alloys
cannot be used at temperatures greater than
ninety five degrees centigrade due to loss
of strength and hardness relatively high density
they have high density you see seven point
one grams per cubic what say centimetre in
comparison to the aluminium two point seven
grams per what say ah cubic centimetre and
magnesium one point seven four grams per centimetre
cube not suitable for applications where weight
is critical so with this we are completing
the zinc alloys next we will see the titanium
cast alloys
titanium is the forth abundant metal on the
earth crust after aluminium iron and magnesium
it is not found in its free right pure metal
in its nature but it is available as oxides
you see it is available as oxides it has got
to similar strength as steel but with a weight
nearly off of steel so this is the greatest
advantage its strength is similar to steel
but its weight is off of the steel highly
it react highly with oxygen nitrogen carbon
and hydrogen difficult to extract so this
is what say difficult to extract and that
is how it is of production cost will be high
now these are the densities of the certain
selected metals now you you see here seven
metals are compared here and the y axis represents
the density and the first one the first one
is the lithium second one is the magnesium
third one is the aluminium forth one is the
titanium fifth one is the iron sixth one is
the nickel and seventh one is the copper now
among all these metals you see copper and
nickel they are and iron they have a got the
higher density and lithium and magnesium have
got the lowest density whereas titaniums density
is moderate now what is the uniqueness of
titanium alloys it has got several what say
is special characteristics
low specific gravity next one it has got high
specific strength next one it is it has got
non magnetic properties next one it is biocompatible
that is how it is used in the what say surgeries
say human implants are made up of titanium
alloys why because it is biocompatible next
one it is it has got the high corrosive resistance
you see the specific gravity of titanium is
four point five grams per centimetre cube
about fifty percent of nickel or copper or
sixty percent of steel so its specific gravity
is very less compared to nickel copper or
steel next one what about the specific strength
specific strength of titanium is about three
times as aluminium and higher than stainless
steel so that is again a great advantage
next one nearly perfectly nonmagnetic next
can be used as bio transplants and finally
titanium has highest corrosive resistance
to sea water and almost every corrosive environment
again this is a very good advantage now these
are the applications of the titanium alloys
aerospace applications for making civil military
and space components for biomedical applications
orthopaedic implants bone screws trauma plates
dental fixtures and surgical instruments and
so on all these are made up of the titanium
alloys next one chemical plants petrochemical
offshore metal finishing pulp and paper industries
in all these what say industries titanium
alloys are used
next one sports items like motor racing components
sports equipments so these are also made up
of titanium alloys and finally marine applications
also made up of titanium alloys now this is
a golf sticks made up of titanium alloys you
see so these are made up of titanium alloys
next one titanium knee hinge joint and you
can see here so this is the titanium joint
so made up of titanium alloys so this is the
titanium hip joint you see so these are used
for the hip replacement titanium dental implants
you see so these titanium dental implants
are very useful in the dental what say surgery
aircraft turbine blades made up of titanium
alloys you see this is the aircraft turbine
blade
alloying elements of titanium one is the alpha
stabiliser second one is the beta stabiliser
and third one is the neutral under the alpha
stabiliser we have aluminium oxygen and a
nitrogen under the beta stabilisers we have
molybdenum vanadium tungsten tantalum and
so on under the neutral we have zirconium
silicon and tin now this is the classification
of the titanium alloys alpha and near alpha
titanium alloys alpha plus beta titanium alloys
beta titanium alloys so there are three types
of titanium alloys so under the alpha under
near alpha titanium alloys we have titanium
aluminium oxygen alloys where aluminium content
will be four to six and they are generally
non heat treatable and weldable they have
medium strength good creep strength good corrosion
resistance under the alpha plus beta titanium
alloys we have titanium aluminium chromium
vanadium copper molybdenum ah tungsten tantalum
alloys
they are heat treatable good farming properties
they have medium to high strength and good
creep strength under the beta titanium alloys
we have titanium aluminium molybdenum chromium
zirconium alloys heat treatable and readily
formable they have high strength and low ductility
casting of titanium alloys casting of titanium
alloys is done in three ways one is the conventional
casting second one is the investment casting
and the third one is the vacuum die casting
in the conventional casting we have to make
the sand mode and we have to melt the metal
and we have to pour the molten metal into
the sand mode so that is the what say conventional
casting in the investment casting we have
to make a wax pattern so parallelly we will
be making a ceramic slurry
the wax pattern will be dipped inside the
ceramic slurry taken out and a stucco dry
stucco we have sprinkled on that pattern then
again it is dipped inside this slurry taken
out and so what say stucco is sprinkled so
this process is repeated maybe six seven times
till a thick shell is created around the wax
pattern then the wax pattern inside the shell
is drained out then the shell is what say
ah dried and it is what say burnt for gaining
additional strength then the molten metal
will be poured inside the shell so that is
the principle involved in the investment casting
so the titanium alloys are also made by ah
castings are also made using investment casting
and titanium alloys can also castings can
also be made by using vacuum die casting here
in the conventional casting we use the rammed
graphite and in the investment casting we
use the yes ah ah wax pattern and we dip it
inside the ceramic slurry and in the vacuum
die casting vacuum is applied for the die
casting to reduce gas entrapment during metal
injection and here we can see this is the
vacuum die casting
so here you can see there is a ah what say
cylinder and here we can see there is a plunger
and here we pour the molten metal after pouring
the molten metal the plunger will be pushing
the molten metal and this is the cavity and
here you can see the cavity the molten metal
will be injected inside the cavity so it is
possible that atmosphere or air present around
the what say molten metal may react with the
metal and the casting will be damaged oxidation
takes place
so for that purpose we use the vacuum so that
ah there wont be any what say air inside only
molten metal is there so it is free from the
oxidation so titanium castings are normally
near net shape products with minimised metal
waste so that is another what say advantage
of the titanium castings so in this lecture
friends we have learnt about the copper alloys
zinc alloys and titanium casting alloys three
casting alloys we have completed in this lecture
so we will meet in the next lecture
thank you
