Crystallographic analysis of lath martensite in a 13Cr-5Ni steel by electron backscattering diffraction

Morphology observation and crystallographic analysis of lath martensite in 13Cr-5Ni steel were investigated by electron backscattering diffraction (EBSD) in a scanning electron microscope. The pole figures of the microstructure measured by EBSD showed that the martensite in this steel held the Kurdjumov–Sachs (K–S) orientation relationship, and the boundary misorientations after the austenite–martensite transformation were also analyzed. However, not all the 24 possible variants in the K–S relationship were observed in a single prior austenite grain. Sub-blocks with special combinations were observed, which can be explained by the minimization of the total shape strain between the adjacent variants introduced during the martensite transformation and relatively low carbon content in the 13Cr-5Ni steel.