eli5: if steel is made by mixing carbon and iron at high temp, what happens when you add carbon to other metals like brass, copper or gold? does it make “brass steel”?
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Carbon can dissolve in iron up to a few percent. Carbon cannot dissolve in most other useful metals very much. Even if it did whether it would then be a useful material depends on a host of factors. Carbon makes iron hard as the microscopic grains of iron-carbon compound stop the iron moving about at an atomic level (technically pinning disclinations if you want to search for it).
There’s a pretty simple answer to this one: Steel is an expression of Carbon (C) and Iron (Fe) and their relative ‘sizes’. C happens to be just the right size and chemistry to fit into spaces in a crystal lattice of Fe. When done right this greatly strengthens that crystal structure, which is achieved through cycles of heating and quenching to specific temperatures. Specifically when you heat up Fe enough and dope it with C, then really rapidly cool it, the C prevents the Fe crystal structure from relaxing back into its original shape. The result gives us a really hard, durable material called Steel.
There are other alloys of metals, brass being one you mentioned, but they aren’t Carbon alloys because only Fe really fits the bill for that specific size, chemistry, and crystal lattice.
(Note, it isn’t strictly true that *only* Carbon fits the bill, you can get Nitrogen and Boron steels and so on, but this is a SUPER complex topic that can’t be fully covered here)
You can make carbide alloy out of copper, brass and gold. It’s just that, iron’s property *benefits* by being mixed with carbon at very high temperature. Gold doesn’t rust. Why the need to make it a carbide?
Copper is often alloyed with other elements like tin to form bronze, or zinc to form brass, to enhance its properties. Carbon doesn’t enhance any of copper’s properties.
generally, you get metal carbides. usually quite hard but brittle materials with fantastic heat resistance.
there are exceptions. IIRC a pure copper-carbon compound is a novel explosive.
Many metals can be combined with carbon to adjust their material properties.
Tungsten Carbide is incredibly useful for cutting tools.
That’s exactly what brass actually is – a mixture of copper with zinc, which greatly improves its material properties.
Brass is basically a “copper steel” – same with bronze.
Ultimately – most *pure* metals are actually quite weak in their pure elemental state. Once we start adding different materials (which we experiment with to find the best additives for each, depending on what we want) we make them stronger in what’s known as an “Alloy”.
Steel is an alloy of iron. There are many forms of it, just like there are many alloys of aluminium, brass, etc.
Welcome to metallurgy.
There’s also something called silicon bronze, which utilizes silicone in a similar fashion to the carbon in steel. It is often used for materials requiring better conductivity than steel, since stainless steel has some resistance passing current through the chromium layer.
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