The Super Alloys

When it comes to word super it is something more powerful and reliable than that what is normal or can say what is available.
So alloy which are super to what is normal or common i.e., steel is called as Super Alloy.
The question comes,how much?
5 times!!!
A material stronger than steel which itself is available to bear the railway carriages and whole building structures!!!!
Yes.It is.
Thus,used for super works like in nuclear reactors,aircraft turbine components,rocket engines and petrochemical equipment.
 Considering them it is used where we need to prevent any kind of oxidation,corrosion,resist high temperature without compromising the wear resistance,hardness and strength. 

                   Figure of simulation of temp. profile of oxidiser from vane of aerospike engine                                                                                                                                                                         

                                                                Figure. Corroded turbine blades

  So what are they made made of?
These are alloys of Cobalt,Nickel, Aluminium and Iron.They have refractory metals too like Chromium,Niobium,Molybdenum,Tungsten and Titanium.
Too much data!!!Isn't it?
                                                                                                                                                                              
The best way to learn them is to co-relate how each element helps the super alloy to work super.
So sugar,spice and everything nice!Here it comes!

1.Cobalt:  This material makes alloy resist heat,wear and corrosion.Though Cobalt is highly radioactive in intense reactions so we can simply restrict its composition there.
2.Nickel: It provides high oxidation resistance and decreases coefficient of thermal expansion.One mentioned condition sorted.
3.Chromium:Corrosion resistance is what it gives us.
4.Titanium and Niobium:They form stable carbides and prevents corrosion and wear.
5.Molybdenum:It increases creep resistance ,the property due to which the material can sustain load for more time even at high temperatures.The word creep should better be learned as"high temp,long time".
6.Tungsten:Tungsten is my favorite element!!It contributed to engineering like Captain America to Avengers.Tungsten maintains the hot hardness and hot strength
7.Aluminium:The powerful deoxidiser which refines grain.Too much amount still can react with iron and can form brittle iron aluminates.

The alloys named are Hastealloy,Inconel ,Nimonics,Waspaloy etc.

Such materials not necessary to provide only the mentioned set of properties.
Their variation in composition can make other charateristics dominate too.
Example:Good weldability,desired resistivity.
The composition is made according to what properties we want and what materials and processes are available to get the alloy.
Companies like Tesla Motors,SpaceX,Ford use them .And Elon Musk,The SpaceX CEO announced a super alloy Inconel in June 2018.

 Figure of Hastealloy pipe fittings

Figure of Inconel turbine blades