Steel; cementite, heat-treating, and all that sort of stuff

[cucumber]

hello.

need to know several things;

1. what exactly is the stuff that i keep reading about called "cementite", and what does it do to the metal
on an atomic scale to make it harder and more brittle?

2. how does heat-treating and quenching (ie. heating a steel blade, let's say, and then dunking it into oil,
or whatever it is they use) help to harden steel?

3. do they use ceramics for blades nowadays, and if they do, what advantages/disadvantages
do they have?

4. i forgot, might be added later on...


if you have an answer to any of the above, it would be splendiferous to hear it. thanks.

 

[Evalesco]

1. Cementite is a chemical compound consisting of iron and carbon, with a formula of Fe3C. It forms during the cooling process of some steels, when the ratio of carbon to iron is between 6.67% and 7.8%. It is hard and brittle and helps to increase the hardenability of steel. On an atomic scale, cementite provides an additional barrier to the movement of dislocations, making it harder and more brittle.

2. Heat-treating and quenching can help to harden steel by changing the microstructure of the material. When steel is heated, its crystal structure changes, resulting in a softer material. Quenching the steel quickly locks the atoms into place, which makes it harder. The increased hardness provided by heat-treating and quenching can also make steel more brittle.

3. Ceramics are not typically used for blades, due to their brittleness and lack of toughness. However, they do have some advantages over steel, such as higher temperature resistance, lower weight, and corrosion resistance. The main disadvantage of ceramics is their cost, which is usually much higher than that of steel.