Crystallography of δ→γ phase transformation during laser-powder-bed-fusion of 17-4 PH martensitic steel
DOI:
https://doi.org/10.54708/26587572_2026_822549Keywords:
phase transformations, martensitic steel, laser powder bed fusion (L-PBF), electron backscatter diffraction (EBSD)Abstract
This work was undertaken in order to shed some light on a poorly explored phase transformation of d-ferrite to austenite (d→g) in steels. To this end, electron backscatter diffraction (EBSD) was employed to characterize the microstructure fabricated by laser powder bed fusion (L-PBF) of 17-4 PH martensitic steel. It was found that the phase transformation involved two different mechanisms, i.e., the displacive and diffusion-driven ones. The orientation relationship between the d-ferrite and austenite spanned a wide range between the “classical” Kurdjumov–Sachs and Nishiyama-Wasserman relationships. Notably, the phase transformation was governed by a strict selection of crystallographic variants with a distinct preference for twin-related variants.References
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