Figure 1

Orientation of bcc-α′ martensites.

(a), TEM images taken at the top surface layer of 304 stainless steels after SMAT. High density of bcc-α′ formed at the intersection region of two hcp-ε plates. (b–f), TEM images and the corresponding live FFT spots patterns taken along the zone axis . Different from the α′ martensite in (b), that in (c) has grown into two hcp-ε plates. The green and white dash lines in (c) indicate the α′main body with Pitsch orientation relationships (OR), with the parts grown into ε transforming into two Kurdjumov-Sachs (K-S) ORs, with respect to the fcc-γ. (g), Schematic summarizing the diffraction spots taken from adjoining phases in the interfacial transition regions between γ, ε and α′. The black arrows indicate the three ORs with details on parallel planes and the red arrows indicate the 5.26° misorientation angle between the Pitsch OR and either of the two K-S ORs. Scale bars, 200 nm (a), 5 nm (b), 10 nm (c).