Intergranular fracture stress and phosphorus grain boundary segregation of a Mn-Ni-Mo steel

Development of Micro Tensile Testing Method in an FIB System for Evaluating Grain Boundary Strength

“…The level of these phosphorus monolayer coverages causing the grain boundary fracture was consistent with the reported level. However the intergranular fracture stress presented by Naudim et al 7) was 2300 MPa to 1700 MPa for the phosphorus monolayer coverage of 0.1 to 0.4, and was much larger than those obtained in the present study. This difference may be due to the effects of specimen shape and constraint by surrounding grains depending on the specimen size.…”

“…The relationship between intergranular fracture stress and phosphorus grain boundary concentration of Mn-Ni-Mo steels has been reported by Naudim et al 7) They showed that the amount of intergranular fracture increased with phosphorus monolayer coverage and that there existed a threshold value in phosphorus monolayer coverage (5 to 10%) at temperatures below À60 C. They also showed that the intergranular fracture stress linearly decreased with phosphorus monolayer coverage from cleavage fracture stress (2300 MPa) at the threshold value in phosphorus monolayer coverage. Nakata et al 8) have also reported that the fracture stress decreased due to non-hardening embrittlement on thermally aged material with high proportion of intergranular fracture and that a threshold value for the intergranular fracture phenomenon existed around the P/Fe peak height ratio of 0.1 (corresponding to the phosphorus monolayer coverage of 0.16).…”

Synergetic effect of hardness and phosphorus grain-boundary segregation on the ductile-to-brittle transition temperature of 17-4 PH steel

“…Based on this assumption, we will now go further and propose an interpretation of the synergetic effect previously mentioned (Section VI) between hardness and segregation on the DBTT. We will make the assumption that the cleavage stress does not depend on the temperature, [15,16] or on the yield strength of the steel. On the other hand, intergranular fracture stress is supposed to decrease when temperature increases.…”

Thermodynamic Alloy Design of High Strength and Toughness in 300 mm Thick Pressure Vessel Wall of 1.25Cr-0.5Mo Steel

“…Mo had the largest effect in delaying the ferrite nose time delay, next to Mn. Mn and Mo generally became segregated in the austenite grain boundaries and suppressed the generation of ferrite [26,27]. The inhibitive effects of Mn and Mo on ferrite formation were greater than those of C alloying.…”