Crystallographic investigation on the serrated grain boundaries in an AISI 316 stainless steel

Abstract

Crystallographic analysis has been carried out on the serrated grain boundaries, which can be frequently observed at the early stage of M23C6 precipitation in an AISI 316 stainless steel. Microstructural observation reveals that the serrated grain boundaries, which were formerly planar in shape before aging treatment, are produced by the serration during aging treatment. Crystallographic features of the serrated grain boundaries were obtained through transmission electron microscopy. Moreover, atomistic approach to the serrated grain boundary was applied to calculate the coincidence points between the two neighboring grains. Both investigations indicate that by serration at the incipient stage of M23C6 precipitation, the interfacial free energy of the grain boundary can be lowered even though the grain boundary area is increased.