scholarly journals Formation and reversion of strain induced martensite on Fe-Cr-Ni alloys

2013 ◽  
Vol 66 (2) ◽  
pp. 221-225 ◽  
Author(s):  
Gabriela Lujan Brollo ◽  
Paulo Roberto Mei
Keyword(s):  
Metastable Phase ◽  
Cold Deformation ◽  
Austenitic Stainless Steels ◽  
Austenitic Steels ◽  
X Ray Diffraction ◽  
Ni Alloys ◽  
Wide Range ◽  
High Nickel ◽  
Strain Induced Martensite ◽  
Incoloy 800

Austenitic stainless steels represent a significant portion of the alloys used in the aeronautical, chemical, shipbuilding, food processing and biomechanical industries. They combine good mechanical properties with high corrosion resistance. When subjected to cold deformation, these steels exhibit a metastable phase called: strain induced martensite (ferromagnetic), whose formation increases mechanical strength and formability, allowing for a wide range of applications. Heated from room temperature, the strain induced martensite transforms to austenite (non-magnetic). It is easy to find information in literature about the strain induced martensite for 18Cr/8Ni austenitic steels, but there is no data for high nickel alloys like A286 (26Ni, 15Cr), Incoloy 800 (30-40 Ni, 21Cr) and Inconel (50Ni, 19Cr). Therefore, this study aimed to verify the formation of strain induced martensite after cold working in Fe-18Cr base alloys with the addition of up to 60 %Ni. The reversion of this phase to austenite after annealing up to 600 ºC was also studied. Optical microscopy, magnetic characterization tests, and x-ray diffraction were used to analyze the transformations.

Structure and Phase Transformations in High Nitrogen and High Interstitial Steels of Different Alloying Systems - Short Review

2021 ◽  
Vol 410 ◽  
pp. 167-172
Author(s):  
Vera V. Berezovskaya ◽  
Eugeny A. Merkushkin ◽  
Ksenia A. Mamchits
Keyword(s):  
Phase Transformations ◽  
Light And Electron Microscopy ◽  
Austenitic Stainless Steels ◽  
Short Review ◽  
Austenitic Steels ◽  
Structure Evolution ◽  
X Ray Diffraction ◽  
High Nitrogen ◽  
Corrosion Properties ◽  
Excess Phases

The features of the structure evolution under thermal effect of Cr, Cr-Ni, Cr-Ni-Mn, and Cr-Mn-austenitic stainless steels with high nitrogen content and a total high content of carbon and nitrogen are analyzed. When studying the structure, we used light and electron microscopy, X-ray diffraction, dilatometry analysis and electrical resistance measurements. Fine structure and aging processes of austenite, nature and morphology of excess phases, as well as character of phase transformations and their relationship with the properties of steels have been studied. It is shown that Cr-Mn-steels with a high content of (C + N), having a homogeneous structure of austenite without excess phases, surpass Cr-Ni austenitic steels in mechanical and corrosion properties, have higher process ability than Cr-Mn-N-steel and are comparable with them in mechanical properties.

Measurement of Residual Stresses by X-ray Diffraction Near Simulated Heat Affected Zones in Austenitic Stainless Steels

1990 ◽  
Vol 34 ◽  
pp. 623-631
Author(s):  
V. S. Iyer ◽  
R. W. Hendricks ◽  
S. A. David
Keyword(s):  
Residual Stresses ◽  
Austenitic Stainless Steels ◽  
Maximum Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Rate Maximum ◽  
Computer Controlled ◽  
Made In

AbstractSimulated heat-affected zones (HAZs) were made in austenitic sta.inless steel specimens using a Gleeble. The samples were heated to temperatures as high as 1100°C by computer controlled resistance heating. By controlling the heating rate, maximum temperature, and cooling rate, a wide range of residual stresses were introduced in the specimens. Stress measurements were made using X-ray diffraction. It was found that significant stress gradients were produced in the simulated HAZs, and that all stresses were compressive in nature, both in the longitudinal and transverse directions. These results are not representative of the residual stresses determined in the HAZs of real welds, thus calling into question some aspects of the role of the Gleeble in such simulations.

HUNTINGTON ALLOY 904L

Alloy Digest ◽  
1983 ◽  
Vol 32 (10) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Iron Alloy ◽  
Austenitic Stainless Steels ◽  
Heat Treating ◽  
Pulp And Paper ◽  
Ss 433 ◽  
Nickel Chromium ◽  
Wide Range ◽  
High Nickel

Abstract HUNTINGTON alloy 904L is an austenitic nickel-chromium-iron alloy with additions of molybdenum and copper. Its high nickel and chromium contents make it resistant to corrosion in a wide range of both oxidizing and reducing environments. The molybdenum and copper additions further improve its resistance to corrosion. Its mechanical properties are similar to those of other austenitic stainless steels. Applications of alloy 904I, include equipment for manufacture and use of sulfuric and phosphoric acids, for fertilizer production and for pulp and paper bleaching. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-433. Producer or source: Huntington Alloy Products Division, An INCO Company.

Processing of Submicron Grained Microstructures and Enhanced Mechanical Properties by Cold-Rolling and Reversion Annealing of Metastable Austenitic Stainless Steels

2007 ◽  
Vol 539-543 ◽  
pp. 4875-4880 ◽  
Author(s):  
Mahesh C. Somani ◽  
L. Pentti Karjalainen ◽  
Antero Kyröläinen ◽  
Tero Taulavuori
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Stainless Steels ◽  
Magnetic Measurements ◽  
Austenitic Stainless Steels ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Strain Induced Martensite ◽  
Austenite Grains ◽  
Nucleation And Growth Mechanism

The effects of chemical composition, cold rolling and subsequent annealing parameters on the reversion of strain-induced martensite to austenite were investigated in three experimental Mn and Si-free Cr-Ni austenitic stainless steels and two commercial Type 301 and Type 301LN grades by optical and electron microscopy, X-ray diffraction and magnetic measurements. Hardness and tensile tests were performed to determine the mechanical properties achieved. In cold rolling, completely martensitic structure could be obtained in the experimental heats, but only partially in 301 and 301LN grades at reasonable reductions. Upon annealing, in 301LN the reversion took place by the nucleation and growth mechanism, and submicron austenite grains were formed within a few seconds at temperatures above 700°C. In the other steels, reversion took place by the shear mechanism, and ultra-fine grains were formed by the recrystallization of austenite at temperatures of 900°C or above. Partial reversion resulted in an excellent combination of yield strength and elongation in 301LN, and also in 301 such ones were attained in the reverted structure even before any profound formation of submicron grains.

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

Effect of Zn Content on Structure, Roughness and Corrosion Behavior of Zn-Ni Alloys

2019 ◽  
Vol 17 (17) ◽  
pp. 17-22
Author(s):  
Hayette Faid
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Stripping Voltammetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ni Alloys ◽  
Sulfate Bath ◽  
Zn Content ◽  
Polarization Test ◽  
Δ Phase

AbstractIn this work, Zn-Ni alloys have been deposited on steel from sulfate bath, by electrodeposition method. The effect of Zn content on deposits properties was studied by cyclic voltammetry (CV), chronoaperometry (CA), linear stripping voltammetry (ALSV) and diffraction (XRD) and scanning electronic microscopy (SEM). The corrosion behavior in 3.5 wt. NaCl solution was examined using anodic polarization test and electrochemical impedance spectroscopy. X-ray diffraction of show that Zn-Ni alloys structure is composed of δ phase and γ phase, which increase with the decrease of Zn content in deposits. Results show that deposits obtained from bath less Zn2+ concentration exhibited better corrosion resistance.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

scholarly journals Machine learning augmented predictive and generative model for rupture life in ferritic and austenitic steels

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Osman Mamun ◽  
Madison Wenzlick ◽  
Arun Sathanur ◽  
Jeffrey Hawk ◽  
Ram Devanathan
Keyword(s):  
Pearson Correlation ◽  
Rupture Life ◽  
Model Performance ◽  
Austenitic Stainless Steels ◽  
Generative Model ◽  
Austenitic Steels ◽  
Gradient Boosting ◽  
Variational Autoencoder ◽  
Feature Importance ◽  
Boosting Algorithm

AbstractThe Larson–Miller parameter (LMP) offers an efficient and fast scheme to estimate the creep rupture life of alloy materials for high-temperature applications; however, poor generalizability and dependence on the constant C often result in sub-optimal performance. In this work, we show that the direct rupture life parameterization without intermediate LMP parameterization, using a gradient boosting algorithm, can be used to train ML models for very accurate prediction of rupture life in a variety of alloys (Pearson correlation coefficient >0.9 for 9–12% Cr and >0.8 for austenitic stainless steels). In addition, the Shapley value was used to quantify feature importance, making the model interpretable by identifying the effect of various features on the model performance. Finally, a variational autoencoder-based generative model was built by conditioning on the experimental dataset to sample hypothetical synthetic candidate alloys from the learnt joint distribution not existing in both 9–12% Cr ferritic–martensitic alloys and austenitic stainless steel datasets.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

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