The role of chemical bonding in grain boundary embrittlement

Control of cryogenic intergranular fracture in high-manganese austenitic steels

“…Briant and Messmer's ,results [64] predict S)Sb)P)C)B. While from their calculations C was found to have little observable effect.…”

“…Boron is perhaps the most widely recognized remedial segregant and is associated with increased resistance to intergranular fracture in many alloys, from ferrit ic Fe-Mn [52,53] to Ni3Al intermetallics [54][55][56]. Both pair-potential theory and the quantum calculations of Briant and Messmer [64] predict that B increases the interfacial cohesion of steels. The effectiveness of B as an alloying addit ion, however, is limited by the presence of relat ively large C and N concentrations which are used as strengthening agents in high-Mn alloys, and would reduce the solubility of boron.…”

“…The chemical bonding aspects of grain boundary embrittlement have recently been explored in greater depth through electronic models [63][64][65][66][67]. Quantum mechanical calculations support the view that embrittling species weaken the chemical bonds.…”

“…Quantum mechanical calculations support the view that embrittling species weaken the chemical bonds. Briant and Messmer [64][65][66] use a molecular orbital cluster method. simulating the local structure at grain boundaries as polyhedra.…”

“…weakening the metal-metal bonds [64]. It is proposed that the weakening of these metal-metal bonds leads to embrittlement.…”