Electron Backscattered Diffraction Observations of Grain Boundary Cracking for a Udimet 188 Alloy During In-Situ Creep Deformation

2007 ◽  
Vol 13 (S02) ◽  
Author(s):  
C Boehlert
Keyword(s):  
Grain Boundary ◽  
Creep Deformation ◽  
Electron Backscattered Diffraction

The evolution of grain-boundary cracking evaluated through in situ tensile-creep testing of Udimet alloy 188

2008 ◽  
Vol 23 (2) ◽  
pp. 500-506 ◽  
Author(s):  
C.J. Boehlert ◽  
S.C. Longanbach ◽  
M. Nowell ◽  
S. Wright
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Creep Deformation ◽  
Surface Deformation ◽  
Coincident Site Lattice ◽  
Tensile Creep ◽  
Face Centered Cubic ◽  
High Angle ◽  
Electron Backscattered Diffraction

In situ scanning electron microscopy was performed during elevated-temperature (⩽760 °C) tensile-creep deformation of a face-centered-cubic cobalt-based Udimet 188 alloy to characterize the deformation evolution and, in particular, the grain boundary-cracking evolution. In situ electron backscatter diffraction observations combined with in situ secondary electron imaging indicated that general high-angle grain boundaries were more susceptible to cracking than low-angle grain boundaries and coincident site-lattice boundaries. The extent of general high-angle grain-boundary cracking increased with increasing creep time. Grain-boundary cracking was also observed throughout subsurface locations as observed for postdeformed samples. The electron backscattered diffraction orientation mapping performed during in situ tensile-creep deformation proved to be a powerful means for characterizing the surface deformation evolution and in particular for quantifying the types of grain boundaries that preferentially cracked.

In situ observation of multiple parallel (1 1 1) twin boundary formation from step-like grain boundary during Si solidification

2020 ◽  
Vol 13 (10) ◽  
pp. 105501
Author(s):  
Kuan-Kan Hu ◽  
Kensaku Maeda ◽  
Keiji Shiga ◽  
Haruhiko Morito ◽  
Kozo Fujiwara
Keyword(s):  
Grain Boundary ◽  
Twin Boundary ◽  
In Situ Observation ◽  
Boundary Formation

scholarly journals Time-Response-Histogram-Based Feature of Magnetic Barkhausen Noise for Material Characterization Considering Influences of Grain and Grain Boundary under In Situ Tensile Test

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2350
Author(s):  
Jia Liu ◽  
Guiyun Tian ◽  
Bin Gao ◽  
Kun Zeng ◽  
Yongbing Xu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Tensile Stress ◽  
Material Properties ◽  
Ferromagnetic Material ◽  
Silicon Steel ◽  
Time Response ◽  
Barkhausen Noise ◽  
Time Interval ◽  
Magnetic Barkhausen Noise

Stress is the crucial factor of ferromagnetic material failure origin. However, the nondestructive test methods to analyze the ferromagnetic material properties’ inhomogeneity on the microscopic scale with stress have not been obtained so far. In this study, magnetic Barkhausen noise (MBN) signals on different silicon steel sheet locations under in situ tensile tests were detected by a high-spatial-resolution magnetic probe. The domain-wall (DW) motion, grain, and grain boundary were detected using a magneto-optical Kerr (MOKE) image. The time characteristic of DW motion and MBN signals on different locations was varied during elastic deformation. Therefore, a time-response histogram is proposed in this work to show different DW motions inside the grain and around the grain boundary under low tensile stress. In order to separate the variation of magnetic properties affected by the grain and grain boundary under low tensile stress corresponding to MBN excitation, time-division was carried out to extract the root-mean-square (RMS), mean, and peak in the optimized time interval. The time-response histogram of MBN evaluated the silicon steel sheet’s inhomogeneous material properties, and provided a theoretical and experimental reference for ferromagnetic material properties under stress.

The Stepwise Cross-sectional Crystalline Analysis of the Stress Induced Voiding in Cu Interconnect

2006 ◽  
Vol 914 ◽  
Author(s):  
Hyo-Jong Lee ◽  
Heung Nam Han ◽  
Suk Hoon Kang ◽  
Jeong-Yun Sun ◽  
Kyu Hwan Oh
Keyword(s):  
Grain Boundary ◽  
Twin Boundary ◽  
Triple Junction ◽  
Hydrostatic Stress ◽  
Electron Backscattered Diffraction ◽  
Cross Sectional ◽  
Copper Interconnect ◽  
Crystallographic Study ◽  
Cu Interconnect ◽  
Planar Electron

AbstractIn a crystallographic study of stress induced voiding of copper interconnect, the planar electron backscattered diffraction analysis showed that the void was initiated at the triple junction of the grain boundaries, not at the junction of the twin boundary and grain boundary. By using stepwise cross-sectional crystalline investigation for the void, it was possible to rebuild 3D crystalline structure near the void. From the stress calculation based on the measured crystalline structures, the hydrostatic stress was highly concentrated at the triple junction of the twin boundary and grain boundary, but experimentally, there was no voiding at that. The voiding in the copper interconnect may depend mainly on the boundary instability.

Influence of Al/Cu content on grain boundary diffusion in Nd-Fe-B magnet via in-situ observation

2019 ◽  
Vol 37 (4) ◽  
pp. 398-403 ◽  
Author(s):  
Xinghua Cheng ◽  
Jian Li ◽  
Lei Zhou ◽  
Tao Liu ◽  
Xiaojun Yu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
In Situ Observation ◽  
Cu Content

Mechanisms of New Orientation Formation during Recrystallization of Old Deformed Aluminium Bicrystals

2005 ◽  
Vol 495-497 ◽  
pp. 1249-1254 ◽  
Author(s):  
Henryk Paul ◽  
Julian H. Driver ◽  
Arnaud Lens
Keyword(s):  
Grain Boundary ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Pure Aluminium ◽  
Local Orientation ◽  
Sample Heating ◽  
Orientation Mapping ◽  
Grain Orientations ◽  
Slip Planes

The crystallography of recrystallization nucleation has been investigated in channel-die deformed pure aluminium bicrystals with {100}<011>/{110}<001> and {100}<001>/{110}<001> orientations. The new grain orientations and misorientations were followed by systematic local orientation measurements using SEM and semi-automatic measurements in a TEM. In particular, orientation mapping combined with in-situ sample heating was used to investigate the formation and growth of new grains and their crystallographic orientation changes at very early stages of recrystallization. Grain boundary migration and ‘consumption’ of the as-deformed areas was always favoured along directions parallel to the traces of the {111} slip planes that had been most active during deformation. The orientations of the first formed nuclei were misoriented with respect to the orientations identified within the neighbouring deformed areas by α(<111>, <112>, or <100>)relations.

Creep Deformation / Oxidation Behavior of Re-Cr-Ni Diffusion Barrier Coated Hastelloy-X at 970°C in Air

2008 ◽  
Vol 595-598 ◽  
pp. 107-116 ◽  
Author(s):  
Shigenari Hayashi ◽  
Mikihiro Sakata ◽  
Shigeharu Ukai ◽  
Toshio Narita
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Barrier Layer ◽  
Creep Deformation ◽  
Diffusion Barrier ◽  
Hastelloy X ◽  
Alloy Substrate ◽  
Barrier Coating ◽  
Diffusion Barrier Layer ◽  
Coated Alloy

High temperature oxidation / creep deformation behavior of a diffusion barrier coated Hastelloy-X alloy, with large grain size ~500μm, was investigated at 970°C in air with external tensile stress of 22.5, 27.5, 32, and 40MPa. The diffusion barrier coating formed on Hastelloy-X consisted of a duplex structure with an inner diffusion barrier layer of Re-Cr-Ni alloy, and an outer oxidation resistant layer of β-NiAl. Un coated bare Hastelloy-X alloy with same grain size was also examined under the same conditions for comparison. The composition of the as-coated diffusion barrier coating was (15~21)Ni, (33~37)Cr, (30~33)Re, (11~15)Mo, and (9~14)Fe. This composition corresponds to σ-phase in the Ni-Cr-Re ternary system, which is known as a topologically close packed, TCP phase. The composition of this diffusion barrier layer did not change during the experiment. The oxide scales formed after creep testing on the coated and un-coated alloy surfaces were needle-like θ-Al2O3, and Cr2O3 with small amount of FeCr2O4, respectively. Grain boundary oxidation was also found in the subsurface region of the un-coated alloy. The Al2O3 scale exhibited severe spallation, and many cracks were formed perpendicular to the stress direction. However, no spallation or cracks were observed in the Cr2O3. The creep rupture times for the diffusion barrier coated alloy were about 1.5 times longer than those for bare alloy at all creep stress conditions. The fracture surface after rupture indicates that fracture occurred along alloy grain boundaries in both the coated and un-coated alloy substrate. Many cavities and cracks were observed within the diffusion barrier coated alloy substrate. These cavities and cracks tended to propagate from the substrate toward the diffusion barrier layer, and then stopped at the Re-Cr-Ni / β-NiAl interface. Cracks formed in the un-coated alloy initiated at the tip of grain boundary oxides, and propagated into alloy substrate. However no major cavities were observed inside the alloy substrate. The stress index, n, for both specimens was about 6, and this indicates that the deformation mechanism of both samples was dislocation creep. These results suggest that the Re-Cr-Ni diffusion barrier layer acts as a barrier against the movement of dislocations at the interface with the alloy surface.

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