High-Resolution Transmission Electron Microscopy Study of Discontinuously Precipitated Ni3Sn

Under appropriate aging treatments Ni–Sn supersaturated solutions (α') decompose at an advancing reaction front into alternating lamellae of Sn-depleted face-centered cubic (fcc) α and DO19 Ni3Sn. This precipitation and the typical defect structures generated within the DO19 compound were investigated by using conventional and high-resolution transmission electron microscopy (CTEM and HRTEM). Complete characterization of defects lying on the basal planes of Ni3Sn lamellae was achieved by HRTEM imaging and iterative digital image matching. The spatial arrangement of stacking faults, rotation interfaces and antiphase boundaries revealed important aspects of the defect formation mechanisms.