scholarly journals Effects of Pulsed Magnetic Fields of Different Intensities on Dislocation Density, Residual Stress, and Hardness of Cr4Mo4V Steel

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 115 ◽  
Author(s):  
Mingdong Hou ◽  
Kejian Li ◽  
Xiaogang Li ◽  
Xu Zhang ◽  
Shaoshi Rui ◽  
...  
Keyword(s):  
Residual Stress ◽  
Magnetic Fields ◽  
Dislocation Density ◽  
Compressive Residual Stress ◽  
Electron Backscatter Diffraction ◽  
Dislocation Motion ◽  
Pulsed Magnetic Fields ◽  
X Ray ◽  
Average Value ◽  
Backscatter Diffraction

To study the effects of pulsed magnetic fields of different intensities on the dislocation density, residual stress, and hardness of Cr4Mo4V steel, magnetic treatment is conducted at 0, 1.0, 1.3, 1.5, 2.0, and 2.5 T. The dislocation density and residual stress are measured using Electron Backscatter Diffraction (EBSD) and X-ray technique, respectively. The results reveal the dislocation density and compressive residual stress decrease at lower magnetic fields such as 1.0 T and 1.3 T, while they increase at higher magnetic fields such as 2.0 T and 2.5 T. The average value of kernel averaged misorientation (KAM) and compressive residual stress decrease about 10.4% and 15.8%, respectively, at 1.0 T, while they increase about 5.88% and 18.2%, respectively, at 2.5 T. The average value of hardness decreases about 3.5% at 1.0 T, from 817 HV to 787 HV. With the increments of intensities, the hardness of the treated samples increases. The hardness essentially remains unchanged at 2.0 T and 2.5 T. The reason for the dislocation motion under the action of pulsed magnetic fields is discussed.

scholarly journals Diffracting-grain identification from electron backscatter diffraction maps during residual stress measurements: a comparison between the sin2ψ and cosα methods

2019 ◽  
Vol 52 (4) ◽  
pp. 828-843 ◽  
Author(s):  
Dorian Delbergue ◽  
Damien Texier ◽  
Martin Lévesque ◽  
Philippe Bocher
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Tilt Angle ◽  
Measurement Errors ◽  
Electron Backscatter Diffraction ◽  
Measurement Techniques ◽  
Single Exposure ◽  
X Ray ◽  
Electron Backscatter ◽  
Backscatter Diffraction

X-ray diffraction (XRD) is a widely used technique to evaluate residual stresses in crystalline materials. Several XRD measurement methods are available. (i) The sin2ψ method, a multiple-exposure technique, uses linear detectors to capture intercepts of the Debye–Scherrer rings, losing the major portion of the diffracting signal. (ii) The cosα method, thanks to the development of compact 2D detectors allowing the entire Debye–Scherrer ring to be captured in a single exposure, is an alternative method for residual stress measurement. The present article compares the two calculation methods in a new manner, by looking at the possible measurement errors related to each method. To this end, sets of grains in diffraction condition were first identified from electron backscatter diffraction (EBSD) mapping of Inconel 718 samples for each XRD calculation method and its associated detector, as each method provides different sets owing to the detector geometry or to the method specificities (such as tilt-angle number or Debye–Scherrer ring division). The X-ray elastic constant (XEC) ½S 2, calculated from EBSD maps for the {311} lattice planes, was determined and compared for the different sets of diffracting grains. It was observed that the 2D detector captures 1.5 times more grains in a single exposure (one tilt angle) than the linear detectors for nine tilt angles. Different XEC mean values were found for the sets of grains from the two XRD techniques/detectors. Grain-size effects were simulated, as well as detector oscillations to overcome them. A bimodal grain-size distribution effect and `artificial' textures introduced by XRD measurement techniques are also discussed.

Comparison of electron backscatter and X-ray diffraction techniques for measuring dislocation density in Zircaloy-2

2019 ◽  
Vol 52 (2) ◽  
pp. 415-427 ◽  
Author(s):  
T. Skippon ◽  
L. Balogh ◽  
M. R. Daymond
Keyword(s):  
Dislocation Density ◽  
Electron Backscatter Diffraction ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
Density Measurements ◽  
X Ray ◽  
Ebsd Data ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Two methods for measuring dislocation density were applied to a series of plastically deformed tensile samples of Zircaloy-2. Samples subjected to plastic strains ranging from 4 to 17% along a variety of loading paths were characterized using both electron backscatter diffraction (EBSD) and synchrotron X-ray line profile analysis (LPA). It was found that the EBSD-based method gave results which were similar in magnitude to those obtained by LPA and followed a similar trend with increasing plastic strain. The effects of microscope parameters and post-processing of the EBSD data on dislocation density measurements are also discussed. The typical method for estimating uncertainty in dislocation density measured via EBSD was shown to be overly conservative, and a more realistic method of determining uncertainty is presented as an alternative.

scholarly journals Effect of Tensile Deformation on Residual Stress of GH4169 Alloy

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1773
Author(s):  
Wenxiang Zhu ◽  
Fei Zhao ◽  
Sheng Yin ◽  
Yuan Liu ◽  
Ronggui Yang
Keyword(s):  
Residual Stress ◽  
Tensile Deformation ◽  
Electron Backscatter Diffraction ◽  
Reduction Rate ◽  
Stress Relief ◽  
X Ray ◽  
Dislocation Movement ◽  
Dislocation Group ◽  
Backscatter Diffraction ◽  
Gh4169 Alloy

In order to reduce the residual stress of the GH4169 alloy, the effect and micro-mechanism of the tensile deformation were studied. The residual stress, dislocation density, and distribution of the GH4169 alloy were analyzed by X-ray residual stress tester, X-ray diffractometer (XRD), and electron backscatter diffraction (EBSD). The results show that: with the increase of tensile deformation, the residual stress relief first increases and then decreases. When the tensile deformation is 3%, the reduction rate of residual stress reaches the maximum, which is 90%. The mechanism of residual stress relief by the tensile treatment is that the dislocation group in the alloy is activated by tensile treatment, and the dislocation distribution in the alloy is more uniform by dislocation movement, multiplication, and annihilation so that the residual stress can be eliminated.

scholarly journals Processing–Microstructure Relation of Deformed and Partitioned (D&P) Steels

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 695 ◽  
Author(s):  
Li Liu ◽  
Binbin He ◽  
Mingxin Huang
Keyword(s):  
Dislocation Density ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Warm Rolling ◽  
High Yield ◽  
Uniaxial Tensile ◽  
X Ray Diffraction ◽  
Bake Hardening ◽  
X Ray ◽  
Backscatter Diffraction

An ultrastrong and ductile deformed and partitioned (D&P) steel developed by dislocation engineering has been reported recently. However, the microstructure evolution during the D&P processes has not yet been fully understood. The present paper aims to elucidate the process–microstructure relation in D&P process. Specifically, the evolution of phase fraction and microstructure during the corresponding D&P process are captured by means of X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). Subsequently, the effect of partitioning temperature on dislocation density and mechanical properties of D&P steel is investigated with the assistance of uniaxial tensile tests and synchrotron X-ray diffraction. It is found that a heterogeneous microstructure is firstly realized by hot rolling. The warm rolling is crucial in introducing dislocations, while deformation-induced martensite is mainly formed during cold rolling. The dislocation density of the D&P steel gradually decreases with the increase of partitioning temperature, while the high yield strength is maintained owing to the bake hardening. The ductility is firstly enhanced while then deteriorated by increasing partitioning temperature due to the strong interaction between dislocation and interstitial atoms at higher partitioning temperatures.

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 Single shot x-ray diffractometry in SACLA with pulsed magnetic fields up to 16 T

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Akihiko Ikeda ◽  
Yasuhiro H. Matsuda ◽  
Xuguang Zhou ◽  
Takeshi Yajima ◽  
Yuya Kubota ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Single Shot ◽  
Pulsed Magnetic Fields ◽  
X Ray

Mitrofanovite, Pt3Te4, a new mineral from the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia

2018 ◽  
Vol 83 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Victor V. Subbotin ◽  
Anna Vymazalová ◽  
František Laufek ◽  
Yevgeny E. Savchenko ◽  
Chris J. Stanley ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Electron Backscatter Diffraction ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Identity ◽  
Polarised Light ◽  
Fe Alloys ◽  
Backscatter Diffraction

AbstractMitrofanovite, Pt3Te4, is a new telluride discovered in low-sulfide disseminated ore in the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia. It forms anhedral grains (up to ~20 μm × 50 μm) commonly in intergrowths with moncheite in aggregates with lukkulaisvaaraite, kotulskite, vysotskite, braggite, keithconnite, rustenburgite and Pt–Fe alloys hosted by a chalcopyrite–pentlandite–pyrrhotite matrix. Associated silicates are: orthopyroxene, augite, olivine, amphiboles and plagioclase. Mitrofanovite is brittle; it has a metallic lustre and a grey streak. Mitrofanovite has a good cleavage, along {001}. In plane-polarised light, mitrofanovite is bright white with medium to strong bireflectance, slight pleochroism, and strong anisotropy on non-basal sections with greyish brown rotation tints; it exhibits no internal reflections. Reflectance values for the synthetic analogue of mitrofanovite in air (Ro, Re’ in %) are: 58.4, 54.6 at 470 nm; 62.7, 58.0 at 546 nm; 63.4, 59.1 at 589 nm; and 63.6, 59.5 at 650 nm. Fifteen electron-microprobe analyses of mitrofanovite gave an average composition: Pt 52.08, Pd 0.19, Te 47.08 and Bi 0.91, total 100.27 wt.%, corresponding to the formula (Pt2.91Pd0.02)Σ2.93(Te4.02Bi0.05)Σ4.07 based on 7 atoms; the average of eleven analyses on synthetic analogue is: Pt 52.57 and Te 47.45, total 100.02 wt.%, corresponding to Pt2.94Te4.06. The density, calculated on the basis of the formula, is 11.18 g/cm3. The mineral is trigonal, space group R$\overline 3 $m, with a = 3.9874(1), c = 35.361(1) Å, V = 486.91(2) Å3 and Z = 3. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Pt3Te4. Mitrofanovite is structurally and chemically related to moncheite (PtTe2). The strongest lines in the powder X-ray diffraction pattern of synthetic mitrofanovite [d in Å (I) (hkl)] are: 11.790(23)(003), 5.891(100)(006), 2.851(26)(107), 2.137(16)(1013), 2.039(18)(0114), 1.574(24)(0120), 1.3098(21)(0027). The structural identity of natural mitrofanovite with synthetic Pt3Te4 was confirmed by electron backscatter diffraction measurements on the natural sample. The mineral name is chosen to honour Felix P. Mitrofanov, a Russian geologist who was among the first to discover platinum-group element mineralisation in the Fedorova–Pana complex.

scholarly journals Precision of the Residual Stress determined by X-ray Diffraction: Summery and Limits

2019 ◽  
Author(s):  
Eckehard Mueller
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
Round Robin ◽  
Surface Treatments ◽  
X Ray Diffraction ◽  
Measurement Standard ◽  
Passenger Cars ◽  
Round Robin Test ◽  
X Ray ◽  
Mechanical Surface

Today components specially for passenger cars are weight optimized. Often it is done by mechanical surface treatments. Therefore, the amount of compressive residual stress induced by the treatment must be known. The measurement is very often done by x-ray diffraction. But how precise can you determine (and not directly measured) the amount? A big question is the calibration of the equipment. A specimen must be designed and calibrated by round robin test, because no measurement standard is available.

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