Z phase precipitation in martensitic 12CrMoVNb steels

Precipitation of Z phase contributes significantly to degradation of creep properties of 12CrMoVNb steels because its precipitation is accompanied by dissolution offinely dispersed nitrides and carbonitrides of M2X and/or MX type. The orientation relationship between Z phase and the ferritic matrix was determined as: $(001)_{\rm z}// (001)_{\alpha}$, $[010]_{\rm z} // [010]_{\alpha}$. Prolonged thcrmal/creep exposure is accompanied by recrystallisation of the matrix and this orientation relationship is destroyed. Nevertheless Z phase particles preserve the form of thin plates. Z phase is a nitride which is rich in vanadium, niobium and chromium and its composition depends on both the temperature of precipitation and the initial chemical composition of steels. The composition of Z phase does not change during long term exposure at the original precipitation temperature. A relationship between the composition of Z phase and its temperature of formation may be able to be used as a temperature exposure indicator of steels. However it is also necessary to know the Z phase composition for a given cast of material

Microstructural aspects of the creep ductility and fracture of unstabilised austenitic CrNiMo steels

26.00; Translated from Czech. (Hutn. Listy 1988 v. 43(9) p. 633-640)Available from British Library Document Supply Centre- DSC:9023.19(VR-Trans--4144)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Needle shaped intergranular precipitates in 08Kh18N10T steel (08Cr10Ni0.5Ti)

Translated from Czech. (Kovove Mater. 1988 v. 26(3) p. 364-380)SIGLEAvailable from British Library Document Supply Centre- DSC:9023.19(VR-Trans--3940)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Statistical normalisation of M23C6 carbides precipitation kinetics, changes in chromium concentration in their vicinity and electrochemical charateristic of EPR tests

International audienc

Intergranular corrosion of AISI 316L steel

International audienceThe degree of sensitization (DOS) of austenitic stainless steel AISI 316L to intergranular corrosion (IGC) was determined by means of electrolytic etching in oxalic acid and electrochemical potentiokinetic reactivation (EPR) tests completed by metallographic inspection. An analytical electron microscope, equipped with an energy-dispersive X-ray spectrometer, was used to examine the microstructure of the steel investigated, which had been annealed for 3.60 x 10(4) to 1.91 x 10(7) s at a temperature of 650 degreesC. The kinetics of precipitation of secondary phases (M(23)C(6) carbides, Laves phase Fe,Mo) were studied by means of quantitative metallography. The volume fractions of chromium-rich M(23)C(6) carbides along grain boundaries and Laves phase Fc Mo in the matrix were determined. Chromium concentration profile measurements across the grain boundary, in the vicinity of M(23)C(6) carbides, have been performed using the analytical electron microscope. All results concerning microstructural changes were quantitatively related to the IGC characteristics by statistical normalizatio