In-grain boundaries

Poor Weldability a. Underbead cracking, high hardness in heat-affected zone. b. Sensitization of nonstabilized austenitic stainless steels. a. Any welded structure. b. Same a. Steel with high carbon equivalents (3), sufficiently high alloy contents. b. Nonstabilized austenitic steels are subject to sensitization. a. High carbon equivalents (3), alloy contents, segregations of carbon and alloys. b. Precipitation of chromium carbides in grain boundaries and depletion of Cr in adjacent areas. a. Use steels with acceptable carbon equivalents (3) preheat and postheat when necessary stress relieve the unit b. Use stabilized austenitic or ELC stainless steels. 

Kingery, W.D. (1981) in Grain Boundary Phenomena in Electronic Ceramics, ed. Levinson, L.M. (American Ceramic Society, Columbus, OH) p. 1. 

Caustic cracking (caustic embrittlement) Intergranular corrosion affects both carbon steels and austenitic steels and accelerated by high stress, higher temperatures, and impurities in grain boundaries. 

Cr23C6 precipitates from solid solution in grain boundaries... 

J.W. Cahn. The impurity-drag effect in grain boundary motion. Acta Metall., 10(9) 789—798, 1962. 

Distribution of pores in grain boundary subjected to tensile stress cr. ... 

V. Randle, The Role of the Coincidence Site Lattice in Grain Boundary Engineering, The Institute of Materials, London, 1996. 

Yoshida, H., Okada, K., Ikuhara, Y., and Sakuma, T., Improvement of high-temperature creep resistence in fine-grained A1203 by Zr4 segregation in grain boundaries , Phil. Mag. Lett., 1997, 76, 9-14. 

Fig. 12. Schematic deformation properties of nanophase ceramics. For ceramics, decreasing the grain size into the nanometer regime corresponds to an increase in grain boundary sliding, resulting in increased ductility of these materials. (Adapted and redrawn from Siegel, 1994.)...

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