Investigation of Relationships between Grain Structure and Inhomogeneous Deformation by Means of Laboratory-Based Multimodal X-Ray Tomography: Strain Accuracy Analysis

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.

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Development of arc welding technique to preclude microsegregation in the dissimilar joint of Alloy C-2000 and C-276

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211000011 ◽

2021 ◽

pp. 095440892110000

Author(s):

B Arulmurugan ◽

M Sathishkumar ◽

D Balaji ◽

K Muralikrishnan ◽

S Pranesh ◽

...

Keyword(s):

Charpy Impact ◽

Hardness Test ◽

Xrd Analysis ◽

Grain Structure ◽

Tensile Fracture ◽

Structure Property ◽

X Ray ◽

Dissimilar Weld ◽

Dissimilar Alloys ◽

Average Grain Size

Hastelloy C-2000 and C-276 are widely used in Flue Gas Desulphurization (FGD) system and Chemical Processing Industries (CPI). Current work is focused on weld microstructure, and mechanical properties (structure-property relationship) of the dissimilar combination of alloy C-2000 and C-276. Multi-pass Pulsed Current Gas Tungsten Arc (PCGTA) welding was adopted for joining the dissimilar alloys using the filler ERNiCrMo-17. Microstructural characteristics of the weld joint were assessed by Optical and Scanning Electron Microscope (SEM). Weld interface microstructure examination revealed the presence of grain coarsening near the Heat Affecting Zone (HAZ) of the alloy C-276 side. SEM analysis shows the absence of secondary Topologically Closed Packed (TCP) phases in the Inter-Dendritic (ID) regions of the dissimilar weld. Micro-segregation of alloying elements in the weldment was assessed by Energy-Dispersive X-ray Spectroscopy (EDS). X-Ray Diffraction (XRD) analysis had been carried out to identify the phase constitution and average grain size. Strength, toughness, and hardness of the dissimilar weld were evaluated with the support of the tensile test, Charpy impact test, and Vicker’s hardness test. Tensile study showed that all the tensile fracture occurred at the base metal side of alloy C-276. The average toughness of the dissimilar alloy joint was noted about 84 J. Hardness test results indicated that fusion zone (FZ) hardness value was 6.19% and 2.27% superior to the candidates’ material (C-276 and C-2000) employed in this study. The refined grain structure and absence of microsegregation resulted in the highest hardness in the dissimilar weld FZ. Results revealed the substantiated use of PCGTA welding for the effective joining of dissimilar alloys of C-2000 and C-276 through the evaluation of metallurgical and mechanical characteristics.

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Depth Profile of Structure, Strain, and Composition in an Annealed Al-Cu-Fe-Cr Quasicrystalline Film

MRS Proceedings ◽

10.1557/proc-695-l12.4.1 ◽

2001 ◽

Vol 695 ◽

Author(s):

M.J. Daniels ◽

D. King ◽

J.S. Zabinski ◽

Z.U. Rek ◽

J.C. Bilello

Keyword(s):

Residual Strain ◽

Incident Angle ◽

Rf Sputtering ◽

Strain Analysis ◽

Grazing Incidence ◽

Grain Structure ◽

Second Phase ◽

Secondary Phases ◽

Composite Target ◽

X Ray

ABSTRACTQuasicrystalline films were formed by RF sputtering from a powder composite target onto Inconel substrates, which produces a polymorphic nanoquasicrystalline grain structure, ~2.5 - 10 nm. Subsequent annealing at 500°C for 4 hours, at base pressures of below 5*10-5 Torr, and with Ar flow to 5 - 10 mT, fully develops the quasicrystalline structure with decagonal phase predominating, except near the termination surface. Analysis by XPS indicated extensive oxygen incorporation and limited aluminum enrichment at the termination surface. These results are correlated with structure and strain analysis via synchrotron grazing incidence x-ray scattering (GIXS). By varying the incident angle, hence the x-ray penetration depth, the evolution of an amorphous and crystalline crystalline secondary phases at the surface of the film has been detected. Residual strain analysis shows that this second phase induces a compressive residual strain of 0.10% as measured from the displacement of the major quasicrystalline peaks in the surface layers of the film.

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Microstructural Development in a TRIP-780 Steel Joined by Friction Stir Welding (FSW): Quantitative Evaluations and Comparisons with EBSD Predictions

Soldagem & Inspeção ◽

10.1590/0104-9224/si2102.04 ◽

2016 ◽

Vol 21 (2) ◽

pp. 146-155 ◽

Cited By ~ 9

Author(s):

Gladys Perez Medina ◽

Hugo Lopez Ferreira ◽

Patricia Zambrano Robledo ◽

Argelia Miranda Pérez ◽

Felipe A. Reyes Valdés

Keyword(s):

Retained Austenite ◽

Shear Fracture ◽

Grain Structure ◽

Microstructural Development ◽

Grain Texture ◽

X Ray Diffraction ◽

Significant Drop ◽

X Ray ◽

Friction Stir ◽

Lap Shear

Abstract The present work describes the effect of FSW on the result microstructure in the stir zone (SZ), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM) of a TRIP-780 steel. X-ray diffraction (XRD), optical microscopy (OM) and EBSD were used for determinations retained austenite (RA) in the SZ, It was found that the amount of RA developed in SZ was relatively large, (approximately 11% to 15%). In addition, recrystallization and the formation of a grain texture were resolved using EBSD. During FSW, the SZ experienced severe plastic deformation which lead to an increase in the temperature and consequently grain recrystallization. Moreover, it was found that the recrystallized grain structure and relatively high martensite levels developed in the SZ lead to a significant drop in the mechanical properties of the steel. In addition, microhardness profiles of the welded regions indicated that the hardness in both the SZ and TMAZ were relatively elevated confirming the development of martensite in these regions. In particular, to evaluate the mechanical strength of the weld, lap shear tensile test was conducted; exhibited the fracture zone in the SZ with shear fracture with uniformly distributed elongation shear dimples.

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Structural Properties of InAs/AlSb Superlattices

MRS Proceedings ◽

10.1557/proc-379-493 ◽

1995 ◽

Vol 379 ◽

Author(s):

B. Jenichen ◽

H. Neuroth ◽

B. Brar ◽

H. Kroemer

Keyword(s):

Buffer Layer ◽

Peak Shift ◽

Lattice Parameter ◽

Structural Quality ◽

Inhomogeneous Deformation ◽

X Ray ◽

Peak Broadening ◽

Short Period ◽

Intensity Ratios ◽

Highly Correlated

ABSTRACTShort-period (InAs)6/(AlSb)6 superlattices (SL) with AlAs-like and InSb-like interfaces (IF) grown on a relaxed AlSb buffer layer are studied by X-ray reflectivity and diffractometry measurements. Reflectivity measurements reveal average IF roughnesses between 0.6 and 1.0 nm. Measurements of the diffuse scattering show that the roughness is highly correlated from layer to layer. Triple crystal area scans illustrate that the inhomogeneous deformation of the buffer layer leads to a certain symmetric peak broadening. In the case of AlAs-like IFs an additional broadening of the SL peaks reveals lattice parameter gradients over the superlattice. This asymmetric peak broadening may be attributed to a further relaxation of the superlattice, which is inhomogeneous with depth. The diffusion of As into the AlSb layers leads to a peak shift and modifies the intensity ratios of the different satellite reflections. The best structural quality is achieved for superlattices with InSb-like IFs.

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X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

Crystals ◽

10.3390/cryst10070555 ◽

2020 ◽

Vol 10 (7) ◽

pp. 555 ◽

Cited By ~ 1

Author(s):

Hadjer Ouaddah ◽

Maike Becker ◽

Thècle Riberi-Béridot ◽

Maria Tsoutsouva ◽

Vasiliki Stamelou ◽

...

Keyword(s):

High Temperature ◽

Defect Formation ◽

Imaging Techniques ◽

Original System ◽

Bragg Diffraction ◽

Grain Structure ◽

Structural Defects ◽

X Ray ◽

In Situ Investigation

To control the final grain structure and the density of structural crystalline defects in silicon (Si) ingots is still a main issue for Si used in photovoltaic solar cells. It concerns both innovative and conventional fabrication processes. Due to the dynamic essence of the phenomena and to the coupling of mechanisms at different scales, the post-mortem study of the solidified ingots gives limited results. In the past years, we developed an original system named GaTSBI for Growth at high Temperature observed by Synchrotron Beam Imaging, to investigate in situ the mechanisms involved during solidification. X-ray radiography and X-ray Bragg diffraction imaging (topography) are combined and implemented together with the running of a high temperature (up to 2073 K) solidification furnace. The experiments are conducted at the European Synchrotron Radiation Facility (ESRF). Both imaging techniques provide in situ and real time information during growth on the morphology and kinetics of the solid/liquid (S/L) interface, as well as on the deformation of the crystal structure and on the dynamics of structural defects including dislocations. Essential features of twinning, grain nucleation, competition, strain building, and dislocations during Si solidification are characterized and allow a deeper understanding of the fundamental mechanisms of its growth.

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Competitive Precipitation and Recrystallization in U-7.5Nb-2.5Zr Alloy

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.354.85 ◽

2014 ◽

Vol 354 ◽

pp. 85-91

Author(s):

Denise A. Lopes ◽

Thomaz Augusto Guisard Restivo ◽

Angelo Fernando Padilha

Keyword(s):

Grain Structure ◽

Main Process ◽

Gamma Phase ◽

X Ray Diffraction ◽

Protective Oxide ◽

X Ray ◽

Key Factor ◽

Cold Rolled ◽

Precipitation Phenomena ◽

Precipitation Events

Abstract. Metallic nuclear fuel plates are nowadays an alternative to the ceramic ones in the sense that the uranium density can be increased at lower enrichment. Higher thermal conductivity is also a key factor favouring such fuels for power reactors. Uranium reacts promptly with oxygen and nitrogen at high temperatures to catastrophic corrosion due to non-protective oxide layers, which imparts hot forming processes. The gamma phase body centred cubic structure can be retained at room temperature by annealing the U-7.5Nb-2.5Zr (wt.%) alloy followed by quenching, where the deformation can be extensive. The resulted highly deformed gamma supersaturated structure is subjected further to competitive recovery/recrystallization and phase precipitation phenomena whose are studied in the work. The U-7.5Nb-2.5Zr alloy was melted into plasma and induction furnaces and afterwards annealed to gamma phase. The normalized alloy was cold rolled and underwent isochronal and isothermal treatments. The microstructure evolution was monitored by optical microscopy, X-ray diffraction analysis and hardness measurements. The results show the precipitation events of α” and α+γ3phases are dominant over recovery in the range 200oC < T < 500oC. Above 500oC the recrystallization is the main process leading to softening and initial Vickers hardness recovery. One refined gamma phase grain structure was obtained (~8.0 μm) after annealing at 700oC for 2.5 hours.

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