How are alloys made ?

[Externet]

If you want an alloy of say iron, manganese, phosphor, and germanium; do you melt them with desired proportions in a very, very hot 'blender' and push the 'on' button for a while ?

Or is it more rocket science than that ?

[Mr Skeptic]

A little easier actually. You just need a little mixing, like with a spoon rather than a blender.

[insane_alien]

but the equivalent of a blender is used in industry. its a lot bigger, hotter and slower than your normal household blender but the principle it the same.

 

all you need is an even mix of the materials

[Externet]

OK. A sort of a blender at melting temperature, the size of the wanted batch.

 

In the mentioned alloy example, what trick is needed to prevent the phosphor to stop existing by becoming smoke when gets to ignition temperature way before iron melts?

 

There should be dozens of elements that will refuse to stay 'alive' at high furnace temperatures... how is that controlled ? Simply such alloys are impossible to achieve; or engineering strategies/processes get into play ?

[ydoaPs]

In the mentioned alloy example, what trick is needed to prevent the phosphor to stop existing by becoming smoke when gets to ignition temperature way before iron melts?

Add the molten phosphor after you melt the iron?

[insane_alien]

OK. A sort of a blender at melting temperature, the size of the wanted batch.

 

In the mentioned alloy example, what trick is needed to prevent the phosphor to stop existing by becoming smoke when gets to ignition temperature way before iron melts?

 

There should be dozens of elements that will refuse to stay 'alive' at high furnace temperatures... how is that controlled ? Simply such alloys are impossible to achieve; or engineering strategies/processes get into play ?

 

the wonderful world of gaseous inerts comes into play here. you smother the furnace in nitrogen or if thats not good enough, xenon.

[Wookiee]

Just Like MIG welding but on a BIGGER SCALE. The gas protects the metal from "burning" or reacting with the air because in stead of air the inert gas is there. (haha. sort of rythmed there, didn't even try it)

 

-Randy

[John Cuthber]

I doubt anyone uses xenon. Argon is a whole lot cheaper.

[insane_alien]

I doubt anyone uses xenon. Argon is a whole lot cheaper.

 

yeah thats the one.

 

but in theory any inert substance could be used

[John Cuthber]

Incidentally, it's sometimes possible to make alloys by electroplating them out of a mixture of metal compounds but this doesn't usually work well. Usually one metal comes out fist then the other.

[Mr Skeptic]

Incidentally, it's sometimes possible to make alloys by electroplating them out of a mixture of metal compounds but this doesn't usually work well. Usually one metal comes out fist then the other.

 

That seems interesting. Wouldn't it be hard to control the ratio of substances though? How could that be done? Would changing the voltages and the electrolyte concentration be sufficient to get alloys of any ratio of several substances? If so, it could be useful for making objects with varying alloy type.

[insane_alien]

as john said, one tends to come out first. the electrochemical potentials have to be VERY close for them to come out at the same time.

[Mr Skeptic]

Yes, but is it possible? I would have thought that increasing the voltage sufficiently would allow all the metals to get electroplated and affect the ratios, and the concentrations of electrolytes to have an effect on the ratios.

[John Cuthber]

In a way, its very easy.

Take a mixture of, for example, copper sulphate and iron sulphate in water. Put a couple of platinum electrodes in it and put a current through the solution with a constant voltage.

Initially copper (practically pure) will come out of solution until the concentration is so low that the potential needed to keep it plating out is higher than that needed to plate out iron. Then a mixture of the 2 will come out. (I think people who like Nernst's equation can put some numbers to this).

 

What is much more difficult is to get any control over the relative amounts of copper and iron in the alloy.

[Donn McGann]

Alloys such as steel are usually made by Melting metals in a hearth or giant

High temperature vat usually melted down With Very high ampereage through

a large carbon conductor adding alloy elements in various Percentages,according to the desired properties,or in an old style blacksmiths

crucible,

[Zephir]

..If you want an alloy of say iron, manganese, phosphor, and germanium; do you melt them with desired proportions in a very, very hot 'blender' and push the 'on' button for a while...:

J. Bond [1956]: "Shaken, not stirred"

[nathan3011]

So when you were mixing them all up together or etc then do you need to get the right amounts of them or will they come together on just the smallest amount

 

Thanks guys in advance for the answer!!

[insane_alien]

yes of course you need to get the right amounts.

 

if a recipe calls for a half cup of flour and you only put in a pinch its not going to work. likewise if an alloy requires 2.4% Zn and you only put enough in to make it 0.24% Zn then you do not have the alloy you set out to make.

[pioneer]

When you mix metals and/or elements to make alloys you often get more products than you bargain for. These are expressed in what they call phase diagrams. The alloy is not only a function of the components but also the temperature. Below is a phase diagram of a simple mixture of iron and carbon to make steel.

 

 

One can get Fe3C as ferrite, austenite and cementite. Do you what steel for hammers or steel for springs, since they all seem the same?

 

The phase diagrams get more complicated as we add more components. If you start with four components there are places in the phase diagram where two or three of your ingredients will pop out into a separate phase. This will cause the 4 components blends to come out differently, if you pick the wrong temperature. So need to make sure you have the right temperature. The phase diagram below uses iron, carbon, chromium and molly at 1000C, with tweaks in the carbon allow you to tweak the properties.

 

Edited December 20, 2008 by pioneer