Phase Separation and Precipitation in a PH 17-4 Stainless Steel By Prolonged Aging At 400 °C

1998 ◽  
Vol 4 (S2) ◽  
pp. 96-97 ◽  
Author(s):  
M. Murayama ◽  
Y. Katayama ◽  
K. Hono
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Phase Separation ◽  
Power Plants ◽  
Atom Probe ◽  
Industrial Applications ◽  
Precipitation Reaction ◽  
Medium Temperature ◽  
Probe Field ◽  
Prolonged Aging

Precipitation-hardened stainless steels are important structural materials in a variety of industrial applications in aircraft, chemical and power plants. These steels have a combination of good mechanical properties, corrosion resistance and simple fabrication process. Precipitation reaction in a PH 17-4 stainless steel which contains approximately 3 wt.% of Cu begins with formation of coherent copper-rich precipitate, which subsequently transform to incoherent fee Cu by further aging. By prolonged aging at 400 °C, embrittlement occurs as hardening progresses. Both the coarsening of Cu and the decomposition of the martensite matrix could be the reasons for this embrittlement. Thus, this study attempted to clarify the phase separation and the precipitation processes in a PH 17-4 stainless steel on prolonged aging by atom probe field ion microscopy (APFIM), in order to understand the mechanism of the degradation of mechanical properties by long term medium temperature aging.

scholarly journals Microstructure and mechanical properties relationship of additively manufactured 316L stainless steel by selective laser melting

2019 ◽  
Vol 5 ◽  
pp. 23 ◽  
Author(s):  
Anne-Helene Puichaud ◽  
Camille Flament ◽  
Aziz Chniouel ◽  
Fernando Lomello ◽  
Elodie Rouesne ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Added Value ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties

Additive manufacturing (AM) is rapidly expanding in many industrial applications because of the versatile possibilities of fast and complex fabrication of added value products. This manufacturing process would significantly reduce manufacturing time and development cost for nuclear components. However, the process leads to materials with complex microstructures, and their structural stability for nuclear application is still uncertain. This study focuses on 316L stainless steel fabricated by selective laser melting (SLM) in the context of nuclear application, and compares with a cold-rolled solution annealed 316L sample. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure and mechanical properties is discussed. It was found that after HT, the material microstructure remains mostly unchanged, while the HIP treatment removes the materials porosity, and partially re-crystallises the microstructure. Finally, the tensile tests showed excellent results, satisfying RCC-MR code requirements for all AM materials.

Characterization of Dissimilar Welded Joints Between Austenitic and Duplex Stainless Steel Grades for Liquid Tank Applications

2018 ◽  
Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Welded Joints ◽  
Industrial Applications ◽  
Duplex Stainless Steels ◽  
Steel Pipes ◽  
Steel Grades ◽  
Welding Processes

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.

3d Mapping Of Light-Element Segregation In 316 Stainless Steel By Atom Probe

1999 ◽  
Vol 5 (S2) ◽  
pp. 116-117
Author(s):  
T. F. Kelly ◽  
D. J. Larson ◽  
M. K. Miller ◽  
J. E. Flinn
Keyword(s):  
Stainless Steel ◽  
Light Element ◽  
Hot Extrusion ◽  
Atom Probe ◽  
Nitrogen Gas ◽  
Probe Field ◽  
Tramp Element ◽  
316 Stainless Steel ◽  
Oxygen Gas ◽  
Counting Statistics

A vanadium-bearing variant of 316 stainless steel that was rapid solidification processed (RSP) by gas atomization and hot extrusion of the powder (10:1 extrusion ratio at 900°C) has been studied previously by conventional atom probe field ion microscopy (APFIM). The mechanical properties of this steel were markedly improved by RSP and aging (600°C for 1000 hours). High nitrogen (0.45 at% (0.2 wt%)) and oxygen (0.16 at% (0.05 wt%)) contents were intentionally introduced by melting under 80% nitrogen/20% oxygen gas and atomizing in nitrogen gas. A nominal boron concentration of 0.04 at% (0.01 wt%)) is present as a tramp element. As a result, a large number density (˜ 2 × 1021 m-3) of 25 nm plate-like vanadium-rich nitrides precipitate during aging of the alloy and these precipitates contribute a major portion of the strengthening. Previous efforts to locate the oxygen in the structure using APFIM were inconclusive largely due to poor counting statistics.

scholarly journals Atom probe field ion microscopy of type 308 CRE stainless steel welds

1995 ◽  
Vol 87-88 ◽  
pp. 207-215 ◽  
Author(s):  
S.S. Babu ◽  
S.A. David ◽  
J.M. Vitek ◽  
M.K. Miller
Keyword(s):  
Stainless Steel ◽  
Atom Probe ◽  
Probe Field ◽  
Field Ion Microscopy ◽  
Ion Microscopy ◽  
Steel Welds

Effect of The Sigma Phase on the Mechanical Properties of a Cast Duplex Stainless Steel during the Ageing Treatment at 850°C

2013 ◽  
Vol 684 ◽  
pp. 325-329 ◽  
Author(s):  
Tian Liang ◽  
Xiao Qiang Hu ◽  
Xiu Hong Kang ◽  
Dian Zhong Li
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Sigma Phase ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Eutectoid Reaction ◽  
Secondary Austenite

With about equal amount of austenite and ferrite in volume fraction, duplex stainless steel (DSS) is in advantage of mechanical properties and corrosive behaviors. Hence it is widely applied to the heavy castings for nuclear power plants inshore, such as impellers, pumps and valves. However, lots of cracks usually occur in these castings during manufacturing processes, because it is susceptible to precipitate the brittle intermetallic compound of sigma phase when the castings are exposed from 600 to 1000oC. In this work, the precipitation of sigma phase was observed by optical microscope (OM) and scanning electron microscope (SEM) in a cast DSS named as MAS/6001, which aged at 850oC from 5 to 300 minutes. The effect of sigma phase on the mechanical properties was analyzed by the tensile at room temperature and impact tests at -10°C. The results show that sigma phase in the MAS/6001 steel precipitated simultaneously with the secondary austenite, which obeyed the eutectoid reaction. The interfaces between austenite or secondary austenite and sigma phase were the locations where cracks generated from the void aggregation. Cracks are susceptible to propagate along or cross these interfaces, and to promote the sigma phase breaking-off, which severely deteriorated the mechanical properties.

Spinodal Decomposition in Fe-Cr-Co Alloys

1982 ◽  
Vol 21 ◽  
Author(s):  
S. S. Brenner ◽  
P. P. Camus ◽  
M. K. Miller ◽  
W. A. Soffa
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Atom Probe ◽  
Continuous Phase ◽  
Miscibility Gap ◽  
Two Phase ◽  
Probe Field ◽  
Long Wavelength ◽  
Composition Fluctuations ◽  
Kinetics Of

Continuous phase separation or spinodal decomposition occurs within a miscibility gap through the selective amplification of long wavelength concentration waves to produce a two-phase modulated microstructure. To comprehensively study the formation of these modulated microstructures and the kinetics of continuous phase separation the behavior of the composition fluctuations in the decomposing material should be monitored directly. The atom probe field-ion microscope is an ideal instrument for this type of investigation of fine-scale microstructures because of its ultra-high spatial resolution and microchemical analysis capability.

On the Physics of Anomalies of Boron Nanosegregation at Dislocations in FeAl

2019 ◽  
Vol 391 ◽  
pp. 246-250
Author(s):  
Yuriy S. Nechaev ◽  
Andreas Öchsner
Keyword(s):  
Mechanical Properties ◽  
Critical Analysis ◽  
Diffusion Processes ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Metallic Materials ◽  
Probe Field ◽  
Ion Microscopy ◽  
And Diffusion

We present results of the constructive critical analysis and interpretation of some recent studies (Blavette, Sauvage, Wilde and others) at the atomic scale (using three-dimensional atom-probe field-ion microscopy) of impurity nanosegregation at dislocations, including “Cottrell atmospheres”, and grain boundaries in deformed intermetallics and metallic materials, and their relevance to mechanical properties and diffusion processes.

scholarly journals Atomistic Analysis Of Radiation-Induced Segregation In Ion-Irradiated Stainless Steel 316

2015 ◽  
Vol 60 (2) ◽  
pp. 1179-1184 ◽  
Author(s):  
G.-G. Lee ◽  
H.-H. Jin ◽  
K. Chang ◽  
B.H. Lee ◽  
J. Kwon
Keyword(s):  
Stainless Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Potential Problem ◽  
Atom Probe ◽  
Atomic Scale ◽  
Dislocation Loops ◽  
Radiation Induced ◽  
Solute Atoms ◽  
Stainless Steel 316

Abstract Stainless steel (SS) is a well-known material for the internal parts of nuclear power plants. It is known that these alloys exhibit radiation-induced segregation (RIS) at point defect sinks at moderate temperature, while in service. The RIS behavior of SS can be a potential problem by increasing the susceptibility to irradiation-assisted stress corrosion cracking. In this work, the RIS behavior of solute atoms at sinks in SS 316 irradiated with Fe4+ ions were characterized by atom probe tomography (APT). There were torus-shaped defects along with a depletion of Cr and enrichment of Ni and Si. These clusters are believed to be dislocation loops resulting from irradiation. The segregation of solutes was also observed for various defect shapes. These observations are consistent with other APT results from the literature. The composition of the clusters was analyzed quantitatively almost at the atomic scale. Despite the limitations of the experiments, the APT analysis was well suited for discovering the structure of irradiation defects and performing a quantitative analysis of RIS in irradiated specimens.

Investigations on Design and Formulation of Buttering Layer Electrode Coatings for Bimetallic Welds

2016 ◽  
Vol 880 ◽  
pp. 37-40 ◽  
Author(s):  
Deepak Bhandari ◽  
Rahul Chhibber ◽  
Navneet Arora ◽  
Rajeev Mehta
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Power Plants ◽  
Welding Process ◽  
Industrial Applications ◽  
Low Alloy Steels ◽  
Shielded Metal Arc Welding ◽  
Delta Ferrite ◽  
Electrode Coating ◽  
Metal Arc Welding

The bimetallic welds (BMWs) between ferritic low alloy steels and austenitic stainless steel are used widely in steam generators of the power plants. The adoption of these welds in wide industrial applications provides feasible solutions for the flexible design of the products by using each material efficiently and economically. The present paper is an effort towards studying the development of austenitic stainless steel buttering filler material for bimetallic weld joint. The work aims at the design and development of buttering layer electrode coatings for shielded metal arc welding process using extreme vertices design methodology suggested by McLean and Anderson to study the effect of electrode coating ingredients on the buttering layer metal composition and delta ferrite content to prevent solidification cracking.

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