Aluminium PDF Print E-mail

 

Aluminum is the expertness of BURAK.Let us distinguish Aluminum for you.


A young metal

There are three main materials group; metals,ceramics and polymers.Aluminum is a material that is placed in metals,the most abundant in this group and also the third most abundant element in the earth.

Although aluminum is the most abundant metal in the world it is a very young metal because of not being pure form in the earth, high energy and production difficulties of getting it in pure form.

The rise in Aluminum demand

  • Energy saving
  • Light weight
  • Convenience in fabrication
  • Recycling
Production stage

Aluminum is produced by electrolise of alumina after gaining alumina from bauxite mine by Bayern process.The main production cost is caused by high energy expenses and process difficulty.But there is an important point;Aluminum is able to recycable.

Example...

The energy that we need for producing 1metric ton aluminum from mine is just 17000 kwh.The energy that we need for producing the same amount of aluminum by recycling scrap is only 250 kwh,and it is true.

Energy saving

Energy-Balance equality conception.

  • E1:The energy cost to produce the material
  • E2:The energy saving by using the material
Aluminum is a light metal,with this property of the metal we save energy at the vehicles like automobiles.There is a high energy cost to use aluminum alloy while we are producing our vehicle.

Let’s take a look at the best of it…

When we buy a vehicle with aluminum body,the energy saving while we are using it is higher than the enery cost of gaining aluminum to produce it.

E2>E1

This situation mustn’t be disregarded for the correct use of the energy sources...

Recycling

The object that we called as scrap for aluminum is nothing more than the production loses that are caused by process conditions or the beverage cans we consumed after drinking.Aluminum is a hundred percent recycable material and this speciality makes its sources unlimited.In the recyling stage it is enough to optimise the casting parameters and control the composition to get first quality production.

Be sure,aluminum is always aluminum,scrap of it includes high worth.

30 percent of the processed aluminum is gained by recycling.70% of aluminum used in electricity , construction and vehicles can be recycled again and again.

Some details...

Recycling of the aluminum beverage cans is 37 percent in Europe and 66,5 percent in America.Recycling of these cans are evaluated quicker and easier because of the consumption speed.But when it comes to aluminum building systems,their occupancy is approximately 50 years according to construction,it takes a long time to recycle aluminum building system profile.

Stimulate the recyling of the aluminum beverage cans for the environment and energy economy .

General properties of the pure aluminum…
  • The third most abundant element in the earth.
  • Bauxite mine is the main raw material.
  • The newest but the most used non-ferrous metal.
  • The minerals that include aluminum are substantially stabile.
  • Physical and chemical properties are depend on the purity.
  • Terminology according to purity:
    1. %99: Low grade purity
    2. %9-99.9: Commercial purity
    3. 99.9-99.95:Super purity
  • Low density
  • High electrical and thermal conductivity
  • High reflection
  • Perfect corrosion resistance
  • High strenght by alloying
  • Suitable for all manufacturing tecnics(casting,plastic deformation,welding, machining,surface treatment)
  • Main empurities are Fe and Si elements in commercial pure aluminum.

Mechanical properties
  • The empurities that exist in the pure aluminum increase the tensile strenght.
Physical properties
  • Melting point; 660.5o
  • Evaporation point; 2494o
  • Solid density; 2699 kg/m3
  • 700o density; 2357 kg/m3
  • 20o thermal expansion; 23x10-6/K
  • 25o thermal conductivity; 237 W/cmK
  • Melting heat; 397J/g
  • Evaporation heat; 10.8 kJ/g
  • Heat capacity; 0.90 J/gK
Atomic and crystal structure
  • Atomic number; 13
  • Atomic mass; 26.98
  • There are different isotopes.Crystal lattice structure is face centered cubic.
  • Co-ordination number is 12.
  • Atomic diamater: 2.86x10-6

Let’s take a technical look at how kind of a mechanism is used to reach the high strenght limits in 6063 Al-Mg-Si alloy that we use in extrusion process.

Precipitation hardening is a three stage mechanism that play an effective role to harden 6063 alloy.

  • Solution heat treatment
  • Quenching
  • Aging
The first two steps are called as press heat treatment and increasing hardness of the metal is providing in these stages.Aging stage is called as thermic process in the industry and the final hardness is gained after this heat treatment.

The pointed black particles with a circle are the Mg2Si intermetallic phases which appears according to alloy composition and the thermomechanical processes.
In a stress moment Mg2Si intermetallic phase blocks the movement of the dislocations,generates new ones and causes dislocation locking. The inhibition of plastic deformation by dislocation locking provides medium strenghts in this alloys.