Is that why steel phases like bainite seem to have both diffusive and dislocative properties, because the dislocations allow "room" for diffusive transformation or the precipitation of carbides like the eta carbides? I ask because I have a theory and correct me if I mess up any of the theory, as you cool the metal it changes phases to reach the lowest energy state (aka equilibrium) when cooled quickly it shears to make martensite and when cooled slowly it diffuses to form pearlite, spheroidite, etc. Bainite seems to have structures from both types of transformation, so if we can create nucleation points for fine grain growth of diffusive phases, dropping the temperature quickly enough to form dislocations but slowly enough to avoid the larger shearing of the martensite phase, would that allow for the lowest possible bainite with minimal (theoretical zero) martensite? It would seem that because of the large shear strains from martensite formation that it reduces the total hardness vs toughness, since bainite is tougher for a given hardness than martensite (probably not by as much as some people claim, but every little bit counts) but is typically too low on the scale of hardness.
My theory is this, as the steel gets closer to equilibrium the driving force of the transformation is reduced, so as dislocations form and carbides diffuse, the total driving force is reduced since the steel is getting closer to equilibrium at that temperature, so the temperature of the steel can be constantly reduced to increase the driving force more, keeping it just above the stress inducing shear effects of martensite, yet dropping fast enough to form a phase hard enough to keep a good edge. I was actually talking to someone related to Frank Richtig, the maker of the so called indestructible blades from Clarkson Nebraska, and this is one theory as to what his heat treat was, constantly reduced temperature kept just between martensite and bainite. Analysis of his blades found lots of extra fine carbide banding, which to my mind seems like it could be related to this combination of diffusion and dislocation with fine eta carbides, and the analysis also shows the grain in his blades most closely match either martensite with an incredibly high tempering temperature (aprox. 900*F) or bainite formed at a really low temperature (right next to martensite start temp). The hardness of his blades is also slightly lower than what some people would consider "ideal" or even remotely acceptable for edge holding in kitchen knives, let alone steel chopping knives.
I'm no metallurgist so I'm probably completely off on this but I am completely fascinated by metallurgy and not just what works but exactly why it works and how to improve it, and reach the maximum potential that I can as a bladesmith and heat treater.
Oh here is my list of steels I mangled the last 30 days: 52100, 5160, CruforgeV, 1084, 15N20, Hitachi Blue#2 & White#2, W2, 1095. When playing a game of grain nucleation & carbide configuration, necessary to varying the carbon volume (locked in carbide and in solution). 