Transformation-induced fine sub-structures in iron-nickel martensites were studied using X-ray diffraction and electron microscopy. The dislocation density, microstrains and twinning increased while the dislocation cell-size (particle size) decreased, with increasing nickel content. Anisotropic particle-size values obtained from X-ray analysis were shown to be due to faulting and/or twinning. From the compound fault probability (1.5α + β) obtained using a Warren-Averbach analysis, and the β values obtained from measured peak asymmetry, stacking-fault probability values were derived and the stacking-fault energy was calculated. By extrapolation of the stacking-fault energy versus composition curve, a stacking-fault energy of 50mJ/m2 was estimated for pure iron.

Comparative X-Ray Diffraction and Electron Microscopic Study of the Transformation-Induced Substructures in the Iron-Nickel Martensites and their Influence on the Martensite Properties. D.K.Chaudhuri, P.A.Ravindran, J.J.Wert: Journal of Applied Physics, 1972, 43[3], 778-88