M23C6 carbides and Cr2N nitrides in aged duplex stainless steel: A SEM, TEM and FIB tomography investigation

Maetz, J.; Douillard, Thierry; Cazottes, Sophie; Verdu, Catherine; Kléber, Xavier

doi:10.1016/j.micron.2016.01.007

Cited by 70 publications

(30 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The microstructure of SDSS alloys usually contain a mixture of primary phases, such as δ-Fe (ferrite) and γ-Fe (austenite), and other secondary phases, such as: σ (Cr-Fe) (sigma), χ (chi), Cr 2 N (chromium nitride), M 23 C 6 (carbides) and γ 2 -Fe (secondary austenite) [27][28][29][30][31][32].…”

Section: Resultsmentioning

confidence: 99%

“…According to the experimental results obtained in this study, increasing the content of σ (Cr-Fe) and δ-Fe phases led to a higher global microhardness. Furthermore, considering also the solution treatment temperature influence on constituent phases, it was shown that during heating at temperatures below 1000 °C [25][26][27][28][29], secondary phases, such as: σ (sigma), χ (chi) and Cr2N are formed [30][31][32][33], being known that these phases exhibit a higher microhardness in comparison with δ-Fe and γ-Fe phases.…”

Section: Resultsmentioning

confidence: 99%

“…Four solution treatment temperatures were selected: 800 • C, 900 • C, 1000 • C and 1100 • C. Considering the sample dimensions and the rapid dissolution kinetics of deleterious secondary phases [14], the solution treatment duration was set to 10 min (0.6 ks) for all treatments, including also the transitory time needed to reach the heat treatment temperature (the samples being fed into the preheated furnace) and the time required for temperature homogenization. At the end of heating, the temperature of each sample was verified by using a laser pyrometer and, after that, the samples were water-quenched (WQ), to preserve the microstructure from high-temperature to ambient-temperature and also to limit intermetallic precipitates formation [30][31][32][33].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Solution Treatment Temperature on Microstructural Properties of an Industrially Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Cojocaru

Şerban

Angelescu

et al. 2017

Metals

View full text Add to dashboard Cite

Abstract:In this present study, the influence of solution annealing temperature on microstructural properties of a forged Super Duplex Stainless Steel (SDSS) was investigated by SEM-BSE (Scanning Electron Microscopy-Backscattered Electrons) and SEM-EBSD (Scanning Electron Microscopy-Electron Backscatter Diffraction) techniques. A brief solution treatment was applied to the forged super duplex alloy, at different temperatures between 800 • C and 1100 • C, with a constant holding time of 0.6 ks (10 min). Microstructural characteristics such as nature, weight fraction, distribution and morphology of constituent phases, average grain-size and grain misorientation were analysed in relation to the solution annealing temperature. Experimental results have shown that the constituent phases in the SDSS alloy are δ-Fe, γ-Fe and σ (Cr-Fe) and that their properties are influenced by the solution treatment temperature. SEM examinations revealed microstructural modifications induced by the Cr rich precipitates along the δ/γ and δ/δ grain boundaries, which may significantly affect the toughness and the corrosion resistance of the alloy. Solution annealing at 1100 • C led to complete dissolution of σ (Cr-Fe) phase, the microstructure being formed of primary δ-Fe and γ-Fe. The orientation relationship between δ/δ, γ/γ and δ/γ grains was determined by electron back scattering diffraction (EBSD). Both primary constituent phase's microhardness and global microhardness were determined.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Solution Treatment Temperature on Microstructural Properties of an Industrially Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Cojocaru

Şerban

Angelescu

et al. 2017

Metals

View full text Add to dashboard Cite

show abstract

“…This behavior is associated with a great amount of γ-phase in the HAZ region which significantly reduces toughness, approximately by half, when the MZ region is evaluated. Furthermore, toughness decreasing at −40˚C is also related to the increase in the concentration of α-phase, and possibly the presence of precipitates of chromium nitride (Cr 2 N), which generates a fragile microstructure with coalescence in the ferrite grains, creating residual stresses and increasing the γ-phase [30] [32]. It is seen that there is an increase in phase grain size and a reduction of the number of grains when the impact resistance is reduced.…”

Section: Toughness Testsmentioning

confidence: 99%

“…Repeated reheating on molten zone (MZ) and heated affected zone (HAZ) may lead to precipitation of secondary austenite and intermetallic phases [32]. Thermal cycles during welding process due to little controlled heating and cooling, can generate gradients of temperature that modify the balance of the austenite/ferrite phases.…”

Section: Toughness Testsmentioning

confidence: 99%

Influence of MIG/MAG Welding Process on Mechanical and Pitting Corrosion Behaviors on the Super-Duplex Stainless Steel SAF 2507 Welded Joints

Lopes¹,

Rodrigues²,

Silva³

et al. 2018

MSA

View full text Add to dashboard Cite

The main objective of this research is to better understand the correlation between the constituent phases presented in the super-duplex steel SAF 2507 when it is under welding process by arc shielding gas MIG-MAG (Metal Inert Gas-Metal Active Gas). Conventional short circuit transfer and derivative STT (Surface Tension Transfer) using the 2594 welding wire as a filler metal and the effects on welding power in hardness, toughness and pitting corrosion are considered here. The results showed that the welding energy (Ew) changed the α/γ-phase's balance and occasionally formed σ-phase in ferrite grain boundaries which led to changes in hardness, toughness and pitting corrosion resistance in molten zone (MZ), heat activated zone (HAZ) and metal base regions (MB). Furthermore, the increased amount of γ-phase improved the pitting corrosion resistance index (PRENγ) mainly in the MZ. This is due to decrease of α-phase fraction and formation of coarser grains, for higher welding energy. The toughness in the MZ decreased with less formation of γ-phase, coalescence of ferritic grains and localized formation of σ-phase, raising the hardness in the HAZ when the welding energy was lower.

show abstract

Multiphase material sample preparation using broad‐beam Ar ion milling for EBSD analyses

Nowakowski¹,

Schlenker²,

Ray³

et al. 2016

European Microscopy Congress 2016: Proceedings

View full text Add to dashboard Cite

When compared to monophase materials, multiphase materials can offer an improvement in properties or introduce new properties. For example, tungsten, carbides, and nitrides do not have many applications as monophase materials; these metals are brittle, which can override their other desirable properties, such as hardness, high temperature stability, and wear. However, when these materials are dispersed in a soft matrix, such as low‐carbon steel, nickel, or cobalt, and form a composite, the multiphase materials are then characterized by desirable mechanical properties, such as ductility, strength, and resistance to creep and fatigue [1,2]. Other types of multiphase materials are protective surface coatings, such as tribological and antioxidation applications, and microelectronics devices [3]. Knowledge of the phases present in the material, their distribution, and their fractions is fundamental to materials characterization. A common investigative approach for engineered materials is electron backscatter diffraction (EBSD) combined with energy dispersive spectroscopy (EDS). EBSD provides information about crystallographic orientations or misorientations and allows the study of grain boundaries, deformation, and recrystallization. EDS can define the chemical composition of the materials. When combined, these techniques permit phase identification with high accuracy [4]. Sample preparation of multiphase materials for EBSD and EDS can be challenging, especially when the different phases have very different characteristics. For example, if one phase is hard and brittle and the second phase is soft and ductile, the rate of material removal during mechanical polishing can vary widely. In addition, the hard particles removed from the first phase can act as a grinding medium and tear the soft matrix of the second phase. The result is a surface inappropriate for EBSD analyses. Electrolytic etching is another sample preparation technique that is not ideal for multiphase materials; it often requires the use of toxic or dangerous chemicals, it can cause differential etching of the sample surface, and it can give the sample surface a varied topography, which will produce a shadowing effect in the EBSD/EDS analysis. The goal of this work is to illustrate how the use of low energy, broad‐beam argon ion milling can improve and facilitate multiphase material sample preparation. Several examples are discussed, including hard particles within a soft matrix and a multiphase protective layer on a metal substrate.

show abstract

M23C6 carbides and Cr2N nitrides in aged duplex stainless steel: A SEM, TEM and FIB tomography investigation

Cited by 70 publications

References 38 publications

Influence of Solution Treatment Temperature on Microstructural Properties of an Industrially Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Influence of Solution Treatment Temperature on Microstructural Properties of an Industrially Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

Influence of MIG/MAG Welding Process on Mechanical and Pitting Corrosion Behaviors on the Super-Duplex Stainless Steel SAF 2507 Welded Joints

Multiphase material sample preparation using broad‐beam Ar ion milling for EBSD analyses

Contact Info

Product

Resources

About