The Development of Interphase Precipitated Nanometre-Sized Carbides in the Advanced Low-Alloy Steels

2013 ◽  
Vol 762 ◽  
pp. 95-103 ◽  
Author(s):  
Jer Ren Yang ◽  
H.W. Yen ◽  
C.Y. Chen ◽  
C.Y. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Random Distribution ◽  
Bearing Steel ◽  
Low Alloy Steels ◽  
Interphase Precipitation ◽  
Orowan Mechanism ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Ledge Mechanism

In this work, the investigation of transmission electron microscopy has elucidated the morphologies of the interphase precipitated carbides in an experimental Ti-Mo-bearing steel into three types: (1) planar interphase precipitation with regular sheet spacing (designated as PIP), (2) curved interphase precipitation with regular sheet spacing (designated as Regular CIP), and (3) curved interphase precipitation with irregular sheet spacing (designated as Irregular CIP). The planar sheets of carbides have also been analyzed and found to be oriented close to ferrite planes {211}, {210} and {111}; the results of transmission electron microscopy provide strong evidence to suggest that the development of interphase-precipitated carbides can be associated with the growth of incoherent ferrite/austenite interface by the ledge mechanism. The sheet spacing and inter-carbide spacing in the sheet have been measured and estimated in this work. The sheet spacing is found to be finer than the inter-carbide spacing in the sheet for all samples investigated. The result reflects that the distribution of interphase-precipitated carbides is anisotropic and cannot be considered random distribution. The relevance of the Orowan mechanism to the non-random distribution of interphase-precipitated carbides has been considered. The contribution of the dispersion of interphase-precipitated carbides to the yield strength of the steel studied has been estimated. It is revealed that an optimum component about 400 MPa contributed by interphase-precipitated carbides can be achieved, and the finding is consistent with the hardness data. Other examples of the different alloy steels are also addressed.

Nanostructure of the rust formed on low alloy steels after exposure tests in a high SOx environment

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 108876-108882
Author(s):  
T. Nishimura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Low Alloy Steels ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Tem Transmission Electron Microscopy

Exposure tests were performed on low alloy steels in a high SOx environment, and the structure of the rust was analyzed by TEM (Transmission Electron Microscopy) and Raman spectroscopy.

scholarly journals Nanobainitic Structure Recognition and Characterization Using Transmission Electron Microscopy/ Rozpoznawanie I Charakteryzacja Struktury Nanobainitycznej Za Pomocą Transmisyjnej Mikroskopii Elektronowej

2014 ◽  
Vol 59 (4) ◽  
pp. 1633-1636 ◽  
Author(s):  
E. Jezierska ◽  
J. Dworecka ◽  
K. Rozniatowski
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bainitic Ferrite ◽  
Lower Bainite ◽  
Bearing Steel ◽  
Density Of Dislocations ◽  
Transmission Electron ◽  
Structure Recognition ◽  
Stress Accommodation ◽  
Microscopy Techniques

Abstract Various transmission electron microscopy techniques were used for recognition of different kinds of bainitic structures in 100CrMnSi6-4 bearing steel. Upper and lower bainite are morphologically different, so it is possible to distinguish between them without problem. For new nanobainitic structure, there is still controversy. In studied bearing steel the bainitic ferrite surrounding the retained austenite ribbon has a high density of dislocations. Significant fragmentations of these phases occur, bainitic ferrite is divided to subgrains and austenitic ribbons are curved due to stress accommodation.

Nanocrystallization Studies in Co and Fe-Rich Amorphous Alloys

1995 ◽  
Vol 405 ◽  
Author(s):  
S. Aburto ◽  
M. Jiménez ◽  
R. Gómez ◽  
V. Marquina ◽  
M. L. Marquina ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Alloys ◽  
Random Distribution ◽  
Spin Orientation ◽  
Scanning Calorimetry ◽  
Magnetic Phases ◽  
Amorphous Ribbons ◽  
Transmission Electron ◽  
Spin Texture

AbstractNanocrystallization from Metglas® 2605 SC and Vitrovac® amorphous ribbons were studied by Mössbauer spectroscopy, transmission electron microscopy and differential scanning calorimetry. The spectra showed spin texture. The relative intensities change to a random distribution of spin orientation. New lines appear indicating new magnetic phases. TEM and DSC observations confirmed the crystallization of nanostructured grains.

scholarly journals High-resolution Transmission Electron Microscopy Characterization of the Structure of Cu Precipitate in a Thermal-aged Multicomponent Steel

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Lizhan Han ◽  
Qingdong Liu ◽  
Jianfeng Gu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Hsla Steel ◽  
Structural Evolution ◽  
High Strength ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Bearing Alloy ◽  
Crystallographic Defects

Abstract High-dispersed nanoscale Cu precipitates often contribute to extremely high strength due to precipitation hardening, and whereas usually lead to degraded toughness for especially ferritic steels. Hence, it is important to understand the formation behaviors of the Cu precipitates. High-resolution transmission electron microscopy (TEM) is utilized to investigate the structure of Cu precipitates thermally formed in a high-strength low-alloy (HSLA) steel. The Cu precipitates were generally formed from solid solution and at the crystallographic defects such as martensite lath boundaries and dislocations. The Cu precipitates in the same aging condition have various structure of BCC, 9R and FCC, and the structural evolution does not greatly correlate with the actual sizes. The presence of different structures in an individual Cu precipitate is observed, which reflects the structural transformation occurring locally to relax the strain energy. The multiply additions in the steel possibly make the Cu precipitation more complex compared to the binary or the ternary Fe–Cu alloys with Ni or Mn additions. This research gives constructive suggestions on alloying design of Cu-bearing alloy steels.

The Nano Carbide Control: Design of Super Ferrite in Steels

2010 ◽  
Vol 89-91 ◽  
pp. 663-668 ◽  
Author(s):  
Hung Wei Yen ◽  
Chi Yuan Huang ◽  
Jer Ren Yang
Keyword(s):  
Precipitation Hardening ◽  
High Strength ◽  
Hardness Measurement ◽  
Isothermal Transformation ◽  
Low Alloy Steels ◽  
Micro Hardness ◽  
Particle Spacing ◽  
Interphase Precipitation ◽  
Transmission Electron ◽  
Alloy Steels

The ferrite phase strengthened by the highly dense nanometer-sized carbides is named super ferrite. The effects of Ti, Ti-Mo, and Ti-Nb micro-alloy additions on the precipitation strengthening in three experimental high-strength low-alloy steels have been investigated by using transmission electron microscopy and micro-hardness measurement. The objective of this work was to study the carbide precipitation under the conditions of isothermal transformation. It was found that interphase precipitation of nano-sized carbide in Steel Ti-Mo had very strong contribution to the hardness of the steel. The distribution of interphase precipitated carbides is associated with both the sheet spacing and the inter-particle spacing, which have been studied. The result implies that (Ti, Mo)C particles possess an excellent effect on precipitation hardening.

Identification of Phases in Alloy Steels after Quenching and after Isothermal Quenching

2012 ◽  
Vol 186 ◽  
pp. 301-304 ◽  
Author(s):  
Julita Smalc-Koziorowska ◽  
Elżbieta Jezierska ◽  
Wiesław Świątnicki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Morphological Characteristics ◽  
Lower Bainite ◽  
Heat Treatments ◽  
Isothermal Quenching ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Diffraction Patterns ◽  
Means Of Transmission

The purpose of the work is the analysis and the identification of phases in alloy steels after various heat treatments by means of transmission electron microscopy. We have investigated the phases formed during austenitising followed by quenching with various rates or by isothermal quenching, as martensite, upper and lower bainite. In order to identify the phases, we used their morphological characteristics and the kind of orientation relationship between the given phase and the austenite. We concluded that the identification of phases occurring in steels after various heat treatments may be performed in a clear manner according to their morphological features combined with the diffraction patterns analysis as observed by transmission electron microscopy.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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