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The present article deals with the analysis of grain-boundary character distribution (GBCD) and microstructural characteristics after iterative processing of austenitic stainless steel, AISI 316L. The steel was subjected to iterative cold reduction and subsequent annealings. After an initial decrease in the fraction of Σ3 boundaries, the number of these increases in subsequent steps. The results relate the importance of iterative processing and the mechanism of obtaining a higher fraction of Σ3 boundaries.

The Ni3Al (L12) intermetallic compound after boron doping becomes ductile. It is argued that grain-boundary segregation is not the only cause of the increase in ductility. It is pointed out that the L12 structure undergoes transformation to D022 during deformation, and during the deformation of this D022 structure the material fails. With the addition of boron, the stability of the L12 structure is enhanced with respect to D022 and slows the transformation rate. Therefore the nucleation and propagation of cracks become inhibited. Numerous experimental observations have been explained with the proposed mechanism.