Degradation of Impact Toughness due to Formation of R Phase in High Nitrogen 25Cr-7Ni-Mo Duplex Stainless Steels.

Precipitation of the Icosahedral Quasicrystalline Phase, R-phase and Laves Phase in Ferritic Alloys

“…Note that the orientation relationship obtained here is the same as that between theFe and R-phase reported in 25Cr-7Ni-0.14N-2.8Mo (mass%) stainless steel, 13) Fe-Cr-W alloy 14) and 0.11C-12Cr-6Mo-10Co (mass%) steel. 15) The chemical composition of the R-phase precipitates determined by TEM-EDS measurement is Fe 53.3, Cr 19.1, W 25.4, Co 2.2 in at% (Fe 34.0, Cr 11.3, W 53.2, Co 1.5 in mass%), which is close to the ratio of constituents for the Rphase Co 5 Cr 2 Mo 3 reported by Komura et al…”

“…The same planes are reported for R-phase in the -Fe matrix of 25Cr-7Ni-0.14N-2.8Mo (mass%) stainless steel. 13) Since the flat surfaces of plate-shaped precipitates are perpendicular to the incident beam and planar faults are almost edge-on in Fig. 4(b), it is found that the flat surfaces are the (14 5 50) planes (plane normal [14 5 50]) and planar faults are the (0001) planes of R-phase as shown in Fig.…”

Correlative EBSD and SKPFM characterisation of microstructure development to assist determination of corrosion propensity in grade 2205 duplex stainless steel

“…For example, phase reactions in the temperature range between 250 and 550°C have been known as '475°C embrittlement' [2-5, 17, 18] where in addition to the degradation of mechanical properties a significant reduction in corrosion performance has also been observed [17][18][19][20][21]. Phase reactions occurring in the temperature range between 600 and 1000°C have become known as 'r-phase embrittlement' where numerous secondary phases, such as Frank-Kasper phases (r and v) and, to some extent, R-phase can be formed [5,10,16,[22][23][24][25][26][27][28][29][30][31][32][33][34][35]. These are often accompanied by the precipitation of nitrides (Cr 2 N and CrN) and carbides [2,4,5,16,34,36,37].…”

Effect of χ Phase on Impact Toughness of 25Cr-7Ni-2Mo-4W Super Duplex Stainless Steel

“…그러나 Mo의 일부를 W으로 치환하면 σ상의 석출은 억제되지만, χ상 및 R상 등과 같은 금속간화합물 의 석출은 조장되는 것으로 알려져 있고 (Ahn and Kang, 2000), 이러 한 금속간 화합물은 시효 초기단계에 석출하여 강도와 연성에는 크게 영향을 미치지 않지만 (Kang et al,2012) 충격인성을 낮추는 것으로 알려져 있다 (Cui et al, 2001 (1) χ상은 시효초기에 석출되었으며 시효처리 시간의 증가와 함께 증가하다 σ 상으로 변태되면서 감소하였다. …”