Determination of Microscopic Strain Distribution in the Martensitic Transformation of Fe-31Ni Alloy Plates Using the Micro-grid Marker Method

The strain distribution due to martensitic transformation in a Fe–Ni alloy was investigated using high-precision markers drawn via electron-beam lithography. This study focused on the strain distribution within the lenticular martensite plate, which developed immediately below the martensite start temperature.The strain in the central region of lenticular martensite was determined to be greater than that near the interface boundary by measuring the displacement at each intersection of the grid markers. This finding is consistent with the shape strain distribution predicted by the phenomenological theory of martensitic transformation based on the microstructure observations.