Transmission electron microscope and scanning auger investigations of temper-embrittled 12% Cr steel

Embrittlement susceptibility induced by impurities segregation to grain boundaries in martensitic steels candidates to be used in ADS

“…In the literature chromium enrichment has been reported in martensitic steels in the annealed and tempered condition and also in these materials with ageing heat treatments [2][3][4][5][6][7][8][9][10]. This chromium enrichment was attributed to segregation in some cases and to the presence of chromium carbides in other studies.…”

“…Therefore, step-cooling produces phosphorus segregation even in the materials not doped with phosphorus although, logically, the maximum segregation is produced in the material doped with this element. It has been reported phosphorus segregation in martensitic steels in the normalised and tempered condition and after ageing heat treatments [2][3][4][5]8,9,16].…”

“…On the other hand, it has also been associated grain boundary phosphorus segregation to the existence of chromium carbides at grain boundaries. It has been reported that phosphorus segregates to the matrix-carbides interfaces [3,5,21].…”

Microstructure evolution and mechanical properties of X12CrMoWVNbN10-1-1 steel during quenching and tempering process

“…This phenomenon could be explained by the residual stress caused by martensite transformation from retained austenite and the stress field formed around Cr-rich M 7 C 3 particles. Mandziej et al [27] found that the Crrich M 7 C 3 carbides formed produced a high stress exerted by them on matrix, which could lead to degradation of the samples. Additionally, through the twice tempering, the variations of the microstructures, including the decomposition of the martensite into polygonal shaped subgrains, contributed effectively to the increase in the impact toughness.…”

The long-term aging embrittlement of Fe-12Cr steels below 773 K

“…[1][2][3][4][5][6][7][8][9][10] The idea that impurities effect the long-term aging embrittlement is primarily based on the strong role of phosphorous on the temper embrittlement of Fe-12Cr steels. [2][3][4][5][6] Microstructural studies report that carbides or Laves phases degrade the toughness of Fe-9 to 12Cr steels upon long-term thermal aging. [7][8][9][10] One comprehensive study of Fe-9Cr-1Mo steel reported that the degradation in toughness was consistent with both grainboundary segregation and microstructural changes.…”