I created a poll so that we can decide once and for all which is the best phase of steel. You can see the poll below, next to the pole. Please feel free to justify your answer below.
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| Steel Poll | Steel Pole |
Steel Poll
Posted on 18 November, 2009 by Mathew
I voted for Bainite. Bainite is the best phase in steel because it gives the most scope to tailor the properties.
From your blog’s name, we know you really like bainite. But, is bainite really a “phase”? Is pearlite also a “phase”?
What would Gibbs say?
I would say in that bainite and pearlite are physically disinguishable that they can be called phases.
Obviously they are not equilbrium phases, and cannot be represented on the equilbrium phase diagram. (or are they?)
We have to acknowledge that if we look in higher resolution at the pearlite phase we can see that it is an intimate mixture of ferrite and cementite. However it’s properties as a mixture are distinct. I don’t think we lose anything by thinking of pearlite as a phase of it’s own.
Similarly if we look as bainite we can see it is an intimate mixture of ferrite and austenite (in carbide free bainite) or ferrite and cementite.
We could justify that pearlite and bainite are represented on the equilibrium phase diagram in the ferrite + cementite phase region. Similarly any other microstructure that forms we could think of as a metastable phase. For example is high carbon martensite, is this a phase? Is it the same as BCC ferrite?
Thanks for question.
“What would Gibbs” say can become the new “what would Jesus say” or “what would Feynman say”.
If I had phrased the question which microstructure is the best I would run into the trouble of mixed microstructures, I guess I can avoid these problems by using the word constituent.
Austenite is the origin.
I think you should not include pearlite as a phase, since it is a mixture of two phases ferrite+cementite.
I agree with what arpan said:Austenite is the origin.hehe.so……