Influence of segregated transition metals on intergranular brittleness of tempered martensitic steels

Thermochemical Interactions Versus Site Competition in Grain Boundary Segregation and Embrittlement in Multicomponent Systems

“…When the attractive i-j interaction is sufficiently high, the more concentrated solute may eventually trap the minor constituent in the matrix in the form of atomic pairs, clusters or precipitates, thus preventing it from segregating to the interfaces [17,18]. The two processes, enhanced co-segregation and gettering, can thus compete according to a complex pattern which depends on the intensity of the i-j interaction, temperature, concentrations of i and j, and on the effects of other elements on both of these two processes [19]. other's segregation at free surface of high purity at 550°C.…”

“…A very crude approach using the above-defined concept of "embrittling potency" EProf the impurity I has been able to show that the M elements driven to grain boundaries in temper brittle steels due to their cosegregation with the embrittlers "intrinsically" modify the embrittlement [19,36]. Mn and Ni strongly increase whereas Mo decreases EPp ( fig.…”

Grain boundary segregation of phosphorus and molybdenum in 2·25Cr–1Mo steel

“…The segregation of phosphorus and molybdenum in the 2 . 25Cr-1Mo steel subjected to the present heat treatments may be taken as equilibrium segregation 3,17 and treated as follows. Assuming that the sites available at the grain boundary are all of the same type, the two elements in the steel may be considered to compete with each other for the sites.…”

“…This has been confirmed both theoretically 6 and experimentally. 17 6) that Mo segregation is beneficial for diminishing temper embrittlement but manganese or nickel segregation is detrimental.…”

Grain boundary segregation of phosphorus and molybdenum in A533B steel

“…The spread of segregation levels is mainly associated with different grain boundary orientations. The segregation of phosphorus and molybdenum in the A533B steel may be taken as equilibrium segregation 5,16 and treated as follows. Assuming that the sites available at the grain boundary are all of the same type, the two elements in the steel may be considered to migrate independently to a fixed number of sites.…”