{225}γ habit planes in martensitic steels: from the PTMC to a continuous model

Fine twinned microstructures with {225}(gamma) habit planes are commonly observed in martensitic steels. The present study shows that an equibalanced combination of twin-related variants associated to the Kurdjumov-Sachs orientation relationship is equivalent to the Bowles and Mackenzie's version of the PTMC for this specific {225}(gamma) case. The distortion associated to the Kurdjumov-Sachs orientation relationship results from a continuous modeling of the FCC-BCC transformation. Thus, for the first time, an atomic path can be associated to the PTMC.