Effect of R-phase on impact toughness of 25Cr-7Ni-4Mo super duplex stainless steel

Effect of Intermetallic Phases on Corrosion Behavior and Mechanical Properties of Duplex Stainless Steel and Super-Duplex Stainless Steel

“…They form at intra and inter granular sites. R-phase is Mo rich compound and their stability increases with increase in Mo content [50,51].…”

“…Above this level material will surely fail due to fracture. Besides σ-phase, other phases like R-phase and 475 O C embrittlement affect the impact toughness of the DSS [50,51,53].…”

“…Impact toughness vs fraction of intermetallic phases [41] degradation of impact energy after aging time of 6 hr and 10 hr for 25Cr-7Ni-N and 25Cr-7Ni-Mo respectively. Hwang et al [51] studied the effect of Rphase on impact toughness of Super DSS. They found that at initial stage of aging at 600 O C, Rphase was formed and later it was transformed to sigma phase.…”

Effects of post weld heat treatments on the microstructure and mechanical properties of dissimilar weld of supermartensític stainless steel

“…According to thermodynamic and kinetics predictions, there are some possibilities for the Mo-rich precipitates formed in the ferrite, including sigma, chi and R phases 12,20,[22][23][24][25][26] . Laves phase R (Fe 2 Mo) precipitate in small quantities between 550 and 650 °C, with a morphology Another possible phase is the metastable χ phase, although some authors have reported its interval of precipitation between 700 °C and 900 °C 23,25 .…”

748 K (475 °C) Embrittlement of Duplex Stainless Steel: Effect on Microstructure and Fracture Behavior

“…[9][10][11] Embrittlement is usually ascribed to spinodal decomposition of the ferrite, namely, the formation of Fe-enriched a¢ phase and Cr-enriched a¢¢ phase, or the formation of Cr-enriched a¢¢ precipitates embedded in a Fe-rich a¢ matrix after aging in the 523 K to 823 K (250°C to 550°C) temperature window. [9,[12][13][14][15][16] Ferrite is not stable within the miscibility gap and, therefore, decomposes into two phases. However, additional phases can also form in the ferrite and coexist with the spinodal decomposition products, such as G and R phase, as well as other secondary phases, [7,[9][10][11][12][17][18][19][20][21][22][23][24][25][26][27] which also can have significant impact on mechanical properties.…”