""The driving force for the martensitic transformation is the instable crystal structure of Austensite at lower temperature. So without forming austenite again. The driving force is gone.""
The point is, at a specific temperature, austenite/martensite ratio will be stable, and lowering the temp changes that ratio to another, stable one..eventually, a temp is reached where all the austenite is gone.
Now, purchase a material, it is delivered, and in your hand..next, assume that what you have in your hand is not fully stable at the atomic level, and if you lower it's temp, a diffusionless process stabilizes the lattice..that is what the cryo process is all about..yes, heat was initially involved, but after you got the material, all you did was cool it..
It's that instability I'm talking about..the austenite to martensite transformation was the easiest example to use to explain diffusionless transformations..
It's the concept of a transformation that occurs as a result of cooling something that is important..
Cheers, John.
PS..be back in a week..on vaca...it's been a pleasure..
The point is, at a specific temperature, austenite/martensite ratio will be stable, and lowering the temp changes that ratio to another, stable one..eventually, a temp is reached where all the austenite is gone.
Now, purchase a material, it is delivered, and in your hand..next, assume that what you have in your hand is not fully stable at the atomic level, and if you lower it's temp, a diffusionless process stabilizes the lattice..that is what the cryo process is all about..yes, heat was initially involved, but after you got the material, all you did was cool it..
It's that instability I'm talking about..the austenite to martensite transformation was the easiest example to use to explain diffusionless transformations..
It's the concept of a transformation that occurs as a result of cooling something that is important..
Cheers, John.
PS..be back in a week..on vaca...it's been a pleasure..