scholarly journals Design of Comb Crack Resistant Milling Inserts: A Comparison of Stresses, Crack Propagation, and Deformation Behavior between Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 CVD Coatings

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 493
Author(s):  
Maiara Moreno ◽  
Idriss El Azhari ◽  
Daniel Apel ◽  
Matthias Meixner ◽  
Wei Wan ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Transgranular Fracture ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Crack Network ◽  
System A ◽  
Compressive Stresses ◽  
Micropillar Compression ◽  
Α Al2o3

Investigations on comb crack resistance of milling inserts coated with chemical vapor deposition (CVD) Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 showed a distinct wear evolution in both systems. Wear studies revealed that the appearance of comb cracks is connected to the initial CVD cooling crack network. Micropillar compression tests indicated a brittle intergranular fracture mechanism for the Ti(C,N) layer and a transgranular fracture accompanied with signs of plastic deformation for the Zr(C,N) coating. Additionally, for the Zr(C,N) based system, a compressive stress condition in the temperature range of interest (200–600 °C) was determined by in-situ synchrotron X-ray diffraction. The set of residual compressive stresses together with the ability of the Zr(C,N) layer to deform plastically are key features that explain the enhanced resistance to comb crack wear of the Zr(C,N) based system in milling of cast iron.

Evolution of texture and internal stresses within polycrystalline rock salt using in situ 3D synchrotron computed tomography and 3D X-ray diffraction

2021 ◽  
Vol 54 (5) ◽  
pp. 1379-1393
Author(s):  
Amirsalar Moslehy ◽  
Khalid A. Alshibli ◽  
Timothy J. Truster ◽  
Peter Kenesei ◽  
Wadi H. Imseeh ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Slip System ◽  
Rock Salt ◽  
Small Scale ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
Crack Network ◽  
X Ray ◽  
Fully Connected

Rock salt caverns have been extensively used as reliable repositories for hazardous waste such as nuclear waste, oil or compressed gases. Undisturbed rock salt deposits in nature are usually impermeable and have very low porosity. However, rock salt formations under excavation stresses can develop crack networks, which increase their porosities; and in the case of a connected crack network within the media, rock salt may become permeable. Although the relationship between the permeability of rock salt and the applied stresses has been reported in the literature, a microscopic study that investigates the properties influencing this relationship, such as the evolution of texture and internal stresses, has yet to be conducted. This study employs in situ 3D synchrotron micro-computed tomography and 3D X-ray diffraction (3DXRD) on two small-scale polycrystalline rock salt specimens to investigate the evolution of the texture and internal stresses within the specimens. The 3DXRD technique measures the 3D crystal structure and lattice strains within rock salt grains. The specimens were prepared under 1D compression conditions and have shown an initial {111} preferred texture, a dominant {110}〈110〉 slip system and no fully connected crack network. The {111} preferred texture under the unconfined compression experiment became stronger, while the {111}〈110〉 slip system became more prominent. The specimens did not have a fully connected crack network until applied axial stresses reached about 30 MPa, at a point where the impermeability of the material becomes compromised due to the development of multiple major cracks.

In situ x-ray study of the γ- to α-Al2O3 phase transformation during atmospheric pressure oxidation of NiAl(110)

2006 ◽  
Vol 21 (12) ◽  
pp. 3047-3057 ◽  
Author(s):  
A. Vlad ◽  
A. Stierle ◽  
N. Kasper ◽  
H. Dosch ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Orientation Relationship ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Oxidation In Air ◽  
Α Al2o3 ◽  
Underlying Substrate

The oxidation in air of NiAl(110) was investigated in the temperature range from 870 °C–1200 °C by in situ x-ray diffraction and transmission electron microscopy. Oxidation at 870 °C and 1 bar oxygen leads to the formation of an epitaxial layer of γ-alumina showing an R30° orientation relationship with respect to the underlying substrate. At oxidation temperatures between 950 °C and 1025 °C, we observed a coexistence of epitaxial γ- and polycrystalline δ-Al2O3. The α-Al2O3 starts to form at 1025 °C and the complete transformation of metastable phases to the stable α-alumina phase takes place at 1100 °C. The fcc-hcp martensitic-like transformation of the initial γ-Al2O3 to epitaxial α-Al2O3 was observed. X-ray diffraction and cross-section transmission electron microscopy proved the existence of a continuous epitaxial α-Al2O3 layer between the substrate and the polycrystalline oxide scale, having a thickness of about 150 nm. The relative orientation relationship between the epitaxial alumina and the underlying substrate was found to be NiAl(110) || α-Al2O3 (0001) and [110] NiAl || [1120].

In Situ Heteroepitaxial Bi2Sr2CaCu2O8 Thin Films Prepared by Metalorganic Chemical Vapor Deposition

1993 ◽  
Vol 335 ◽  
Author(s):  
Frank Dimeo ◽  
Bruce W. Wessels ◽  
Deborah A. Neumayer ◽  
Tobin J. Marks ◽  
Jon L. Schindler ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Oxide Phase ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Metalorganic Chemical

AbstractBi2Sr2CaCu2O8 thin films have been prepared in situ by low pressure metalorganic chemical vapor deposition using fluorinated β–diketonate precursors. The influence of the growth conditions on the oxide phase stability and impurity phase formation was examined as well as the superconducting properties of the films. Thin films deposited on LaAIO3 substrates were epitaxial as confirmed by x-ray diffraction measurements, including θ-2θ and φ scans. Four probe resistivity measurements showed the films to be superconducting with a maximum Tc0 of 90 K without post annealing. This Tc0 is among the highest reported for thin films of the BSCCO (2212) phase, and approaches reported bulk values.

Improved Structural Quality and Carrier Decay Times in GaN Epitaxy on SiN and TiN Porous Network Templates

2006 ◽  
Vol 527-529 ◽  
pp. 1505-1508
Author(s):  
Ümit Özgür ◽  
Y. Fu ◽  
Cole W. Litton ◽  
Y.T. Moon ◽  
F. Yun ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Structural Quality ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Porous Network ◽  
X Ray ◽  
Radiative Efficiency ◽  
Decay Times ◽  
Threading Dislocation Density

Improved structural quality and radiative efficiency were observed in GaN thin films grown by metalorganic chemical vapor deposition on in situ-formed SiN and TiN porous network templates. The room temperature carrier decay time of 1.86 ns measured for a TiN network sample is slightly longer than that for a 200 μm-thick high quality freestanding GaN (1.73 ns). The linewidth of the asymmetric X-Ray diffraction (XRD) (1012) peak decreases considerably with the use of SiN and TiN layers, indicating the reduction in threading dislocation density. However, no direct correlation is yet found between the decay times and the XRD linewidths, suggesting that point defect and impurity related nonradiative centers are the main parameters affecting the lifetime.

scholarly journals Effect of Temperature and Time on Nickel Aluminide Coating Deposition

2018 ◽  
Vol 37 (4) ◽  
pp. 491-496 ◽  
Author(s):  
Ali Dad Chandio ◽  
Shahid Hussain Abro
Keyword(s):  
Nickel Aluminide ◽  
Linear Trend ◽  
Aluminide Coating ◽  
Chemical Vapor ◽  
Effect Of Temperature ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Initial Stage ◽  
Low Activity

The βNiAl coating was deposited onto Nickel based CMSX-4 superalloy by in-situ CVD (Chemical Vapor Deposition) method. Main focus of this contribution was to study the influence of aluminizing time and temperature on the microstructure and thickness of the coating; this was followed by examination by XRD (X-Ray Diffraction), electron microscope. Results suggest that an incremental variation in temperature alters the coating activities from HA (High Activity) to LA (Low Activity). This is exhibited by the resultant CT (Coating Thickness) since HA coatings are thicker than LA counterparts. The microstructure of the coating formed at low temperature (or HA ones) showed a large amount of α-Cr precipitates while one formed at high temperature (or LA ones) exhibited lower amounts of such precipitates. Moreover, incremental aluminizing time showed linear trend of CT at initial stage, thereafter (10 hrs) it leveled off. Whereas it does not affect microstructure of the coating

Chemical Vapor Functionalization of ZnO Nanocrystals

2010 ◽  
Vol 1260 ◽  
Author(s):  
Moazzam Ali ◽  
Marty D. Donakowski ◽  
Markus Winterer
Keyword(s):  
Gas Phase ◽  
Diffuse Reflectance ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
In Series ◽  
Lower Temperature ◽  
Diffuse Reflectance Infrared

AbstractChemical Vapor Functionalization (CVF) is a method in which nanocrystals undergo in situ functionalization in the gas phase. In CVF, two reactors are used in series. The first reactor consists of a hot quartz tube (1073 K) where ZnO nanocrystals are synthesized in the gas phase from diethylzinc and oxygen. The second reactor, connected at the exit of the first one and kept at lower temperature (673 K), is used as functionalization chamber. At the connecting point of the two reactors, vapors of organic functionalizing agents are injected which react with the surface of ZnO nanocrystals. ZnO nanocrystals have been functionalized by 1-hexanol, n-hexanoic acid, n-hexanal and 1-hexylamine. Functionalized ZnO nanocrystals have been characterized by Dynamic Light Scattering, X-ray Diffraction and Diffuse Reflectance Infrared Fourier Transform Spectroscopy.

Mechanical Stresses During Solid State Amorphization of Zr/Co Multilayers

1994 ◽  
Vol 356 ◽  
Author(s):  
M. Moske ◽  
K. Samwer
Keyword(s):  
Thin Film ◽  
Compressive Stress ◽  
High Vacuum ◽  
Kirkendall Effect ◽  
Film Deposition ◽  
Sudden Increase ◽  
X Ray Diffraction ◽  
Compressive Stresses ◽  
Diffusion Paths

AbstractThin film structures of crystalline Zr and Co, deposited in UHV, are investigated by bending beam technique and by X-ray diffraction. During isothermal annealing and interdiffusion reaction of the thin film double layer and multilayer packages large compressive stresses are generated while an amorphous ZrCo-phase is formed. This can, at first hand, be understood in terms of the Kirkendall effect where Co atoms, as the main moving species, lead to a volume increase of the film beyond the Co interface. The observed change in Zr lattice spacing in accordance with the evolution of mechanical stress indicates that the compressive stress is built up particularly within the Zr layer due to the solution of Co in Zr grains during the initial amorphization reaction. Film structures, having Co already present in the crystalline Zr layer after film deposition, show a decrease in reaction kinetics combined with a lower stress level, indicating that the interdiffusion reaction is depending on the stress state in the Zr grains. At late stages of annealing in high vacuum a sudden increase of additional compressive stress is observed, which could be attributed to the oxidation of Zr, very likely due to the formation of diffusion paths for oxygen through the Co (cap-) layer (Kirkendall voids). Such oxidation behavior was not observed with samples measured in situ in UHV directly after film deposition.

Thermal Residual Stress Relaxation in Sputtered ZnO Film on (100) Si Substrate Studied In Situ by Synchrotron X-Ray Diffraction

2011 ◽  
Vol 681 ◽  
pp. 127-132
Author(s):  
Christopher Krauss ◽  
Guillaume Geandier ◽  
Florine Conchon ◽  
Pierre Olivier Renault ◽  
Eric Le Bourhis ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Structural Changes ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Compressive Stresses ◽  
Residual Stress Relaxation

Residual stress relaxation in sputtered ZnO films has been studied in-situ by synchrotron x-ray diffraction. The films deposited on (001) Si substrates were thermally treated from 25°C to 700°C. X-ray diffraction 2D patterns were captured continuously during the heating, plateau and cooling ramps. The corrections carried out for compensating the furnace drift are discussed. We first observe an increase of the intrinsic compressive stresses before stress relaxation starts to operate around 370°C. Then, thermal contraction upon cooling dominates so that overall, the large initial compressive film stresses turn to tensile after thermal treatment. The overall behaviour is discussed in terms of structural changes induced by the heat treatment.

Sign in / Sign up

Export Citation Format

Share Document