Microstructure and Oxidation of a Cast Nickel Aluminide Alloy

2002 ◽  
Vol 753 ◽  
Author(s):  
D. Y. Lee ◽  
M. L. Santella ◽  
I. M. Anderson ◽  
G. M. Pharr
Keyword(s):  
Nickel Aluminide ◽  
Volume Fraction ◽  
Surface Region ◽  
Oxidation Products ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Multivariate Statistical ◽  
Near Surface ◽  
X Ray ◽  
Spectrum Imaging

ABSTRACTSpecimens of the cast Ni3Al alloy IC221M were annealed in air at 900°C to examine the effects of oxidation and thermal aging on the microstructure. The alloy is comprised of a dendritically solidified γ-γ′ matrix containing γ+Ni5Zr eutectic colonies in the interdendritic regions. Microstructures of aged specimens were examined by optical microscopy and energy dispersive X-ray (EDX) spectrum imaging in the scanning electron microscope (SEM). Two primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, and (2) the volume fraction of the γ+Ni5Zr eutectic decreases. Oxidation products were identified using x-ray diffraction and EDX spectrum imaging with multivariate statistical analysis (MSA). During the initial stages of oxidation, the first surface oxide to form is mostly NiO with small amounts of Cr2O3, ZrO2, NiCr2O4, and θ-Al2O3. Initially, oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, a continuous film of α-Al2O3 forms immediately beneath the surface that eventually evolves into a double layer of α-Al2O3 and NiAl2O4. Although these oxides are constrained to the near surface region, others penetrate to greater depths facilitated by oxidation of the γ+Ni5Zr eutectic colonies. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a thin sheath of Al2O3.

Characterization of Reactive Ion Etch Damage in GaAs by Triple Crystal X-Ray Diffraction

1993 ◽  
Vol 324 ◽  
Author(s):  
Victor S. Wang ◽  
Richard J. Matyi ◽  
Karen J. Nordheden
Keyword(s):  
Bias Voltage ◽  
Diffuse Scattering ◽  
Reciprocal Lattice ◽  
Surface Region ◽  
Perfect Crystal ◽  
X Ray Diffraction ◽  
Reciprocal Lattice Point ◽  
Near Surface ◽  
X Ray ◽  
Imperfect Crystal

AbstractTriple crystal x-ray diffraction (TCXD) is a non-destructive structural characterization tool capable of the separation and direct observation of the dynamic (perfect crystal) and the kinematic (imperfect crystal) components of the total intensity diffracted by a crystal. Specifically, TCXD can be used to measure the magnitude of the diffuse scattering arising from defects in the crystal structure in the immediate vicinity of a reciprocal lattice point. In this study, the effects of BC13 reactive ion etching (RIE) on the near-surface region of GaAs were investigated by analyzing the changes in the diffuse scattering using both the symmetric 004 reflection as well as the highly asymmetric and more surface sensitive 113 reflection. While the results from the 004 reflections revealed little difference between the unetched and the BC13-etched samples, maps of the diffracted intensity around the 113 reflections showed an unexpected and reproducible decrease in the extent of the diffuse scattering in the transverse direction (perpendicular to the < 113 > direction) as the RIE bias voltage was increased. This decrease suggests that the degree of etch damage induced in the GaAs near-surface region is reduced with increasing bias voltage and ion energy. Additionally, the symmetry and orientation of the kinematic scattering was altered. Possible mechanisms for these results willbe discussed.

In situ X-ray diffraction study of stacking fault formation in the near-surface region of transformation induced plasticity steels

2013 ◽  
Vol 530 ◽  
pp. 105-112 ◽  
Author(s):  
David Rafaja ◽  
Christina Krbetschek ◽  
Daria Borisova ◽  
Gerhard Schreiber ◽  
Volker Klemm
Keyword(s):  
Diffraction Study ◽  
Surface Region ◽  
Stacking Fault ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Transformation Induced Plasticity ◽  
X Ray

Properties of TiN Coatings Deposited on Nitrogen Ion Implanted Steel C1045

2007 ◽  
Vol 555 ◽  
pp. 59-64
Author(s):  
D. Peruško ◽  
N. Bibić ◽  
S. Petrović ◽  
M. Popović ◽  
M. Novaković ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Strong Dependence ◽  
Surface Region ◽  
Grazing Incidence ◽  
Iron Nitrides ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Tin Coatings ◽  
Nitrogen Ion

The effects of nitrogen pre-implantation of AISI C1045 steel substrates on the properties of deposited TiN coatings were investigated. Nitrogen ion implantations were performed at 40 keV, to the fluences from 5x1016 – 5x1017 ions/cm2. On so prepared substrates we deposited 1.3 μm thick TiN layers by reactive sputtering. Structural characterizations of the samples were performed by grazing incidence X-ray diffraction analysis (GXRD), standard X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). Microhardness was measured by Vicker’s method. The obtained results indicate the formation of iron-nitrides in the near surface region of the substrates, more pronounced for higher implanted fluences. The structure of the deposited TiN coatings shows a strong dependence on the pre-implantation of the substrates, which is attributed to the changed local structure at the surface. Ion implantation and deposition of hard TiN coatings induce an increase of the microhardness of this low performance steel of more than eight times.

Fabrication of CaWO4:Eu3+ Thin Films via Electrochemical Methods Assisted by a Novel Post Treatment

2011 ◽  
Vol 194-196 ◽  
pp. 2458-2461 ◽  
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao ◽  
Jian Xiong Yuan ◽  
Qing Hua Zhang ◽  
Yan Hong Yin ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Electrochemical Techniques ◽  
Surface Region ◽  
Luminescent Properties ◽  
Emission Peak ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4 thin films directly through electrochemical techniques. A novel post processing has been proposed to synthesize CaWO4:Eu3+ thin films at room temperature. X-ray diffraction, X-ray photoelectron spectrometry, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that Eu3+-doped CaWO4 films have a tetragonal phase; the content of Eu in the near surface region is much higher than that of the bulk; under the excitation of 310 nm, a sharp emission peak at 616 nm has been observed for Ca0.9WO4:Eu0.13+ thin films.

scholarly journals Simultaneous scanning near-field optical and X-ray diffraction microscopy for correlative nanoscale structure–property characterization

2019 ◽  
Vol 26 (5) ◽  
pp. 1790-1796 ◽  
Author(s):  
Qian Li ◽  
Samuel D. Marks ◽  
Sunil Bean ◽  
Michael Fisher ◽  
Donald A. Walko ◽  
...  
Keyword(s):  
Multimodal Imaging ◽  
Near Field ◽  
Surface Region ◽  
Crystallographic Structure ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Mechanical Pressure ◽  
Near Surface ◽  
X Ray ◽  
Nanoscale Characterization

A multimodal imaging instrument has been developed that integrates scanning near-field optical microscopy with nanofocused synchrotron X-ray diffraction imaging. The instrument allows for the simultaneous nanoscale characterization of electronic/near-field optical properties of materials together with their crystallographic structure, facilitating the investigation of local structure–property relationships. The design, implementation and operating procedures of this instrument are reported. The scientific capabilities are demonstrated in a proof-of-principle study of the insulator–metal phase transition in samarium sulfide (SmS) single crystals induced by applying mechanical pressure via a scanning tip. The multimodal imaging of an in situ tip-written region shows that the near-field optical reflectivity can be correlated with the heterogeneously transformed structure of the near-surface region of the crystal.

Structural analysis of coexisting tetragonal and rhombohedral phases in polycrystalline Pb(Zr0.35Ti0.65)O3 thin films

2003 ◽  
Vol 18 (1) ◽  
pp. 173-179 ◽  
Author(s):  
Maxim B. Kelman ◽  
Paul C. McIntyre ◽  
Bryan C. Hendrix ◽  
Steven M. Bilodeau ◽  
Jeffrey F. Roeder ◽  
...  
Keyword(s):  
Thin Films ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
Surface Region ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Scattering Geometry ◽  
Pzt Films

Structural properties of polycrystalline Pb(Zr0.35Ti0.65)O3 (PZT) thin films grown by metalorganic chemical vapor deposition on Ir bottom electrodes were investigated. Symmetric x-ray diffraction measurements showed that as-deposited 1500 íthick PZT films are partially tetragonal and partially rhombohedral. Cross-section scanning electron microscopy showed that these films have a polycrystalline columnar microstructure with grains extending through the thickness of the film. X-ray depth profiling using the grazing-incidence asymmetric Bragg scattering geometry suggests that each grain has a bilayer structure consisting of a near-surface region in the etragonal phase and the region at the bottom electrode interface in the rhombohedral hase. The required compatibility between the tetragonal and rhombohedral phases in he proposed layered structure of the 1500 Å PZT can explain the peak shifts observed n the symmetric x-ray diffraction results of thicker PZT films.

Structural characterization of SiGe and SiGe:C heterostructures using a combination of X-ray scattering methods

2004 ◽  
Vol 19 (1) ◽  
pp. 49-52 ◽  
Author(s):  
J. F. Woitok
Keyword(s):  
Structural Characterization ◽  
Surface Region ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Xrd Pattern ◽  
X Ray ◽  
X Ray Scattering ◽  
Single Method ◽  
Ray Scattering

This study is about the structural properties of SiGe and SiGe:C heteroepitaxial layers on Si (001). The structural characterization is based on the application of complementary information content of X-ray scattering techniques like high-resolution X-ray diffraction (XRD), X-ray reflectivity (XRR), and X-ray diffuse scattering (XDS). One main focus of the analysis is to derive a sample model that sufficiently describes all experimental datasets. In addition, the reliability of parameters extracted by just one single method is discussed. It turned out that XRR is more sensitive to the near surface region, indicating the presence of surface roughness and density gradients that do not significantly affect the XRD pattern.

Strain Measurements on Nitrogen Implanted 4H-SiC

2011 ◽  
Vol 679-680 ◽  
pp. 185-188 ◽  
Author(s):  
Matthieu Amigou ◽  
Marie France Beaufort ◽  
Alain Declémy ◽  
Stephanie Leclerc ◽  
Jean François Barbot
Keyword(s):  
Room Temperature ◽  
Surface Region ◽  
Normal Strain ◽  
X Ray Diffraction ◽  
Nitrogen Implantation ◽  
Near Surface ◽  
Strain Measurements ◽  
Strain Profile ◽  
X Ray ◽  
Mechanism Operative

The evolution of the normal strain induced by nitrogen implantation in 4H-SiC was investigated through X-ray diffraction measurements and compared to previous studies on helium implanted SiC. The shape of the normal strain profile in the near surface region shows that the accumulation of point defects is not the only mechanism operative at room temperature. In the highly damaged region, the normal strain profile fits the N concentration.

A short-wave X-ray diffraction method to evaluate the residual stress of welding joint for 7N01 Al alloy

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940047
Author(s):  
Zhiyi Zhang ◽  
Xiaojun Xu ◽  
Zhiqing Sun ◽  
Qibin Tang ◽  
Ren Wang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Welding Process ◽  
Diffraction Method ◽  
High Energy ◽  
Short Wave ◽  
Middle Part ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray

The residual stress with different degree is inevitable to be introduced during the welding process for high strength 7N01 Al alloys, which will deteriorate the mechanical properties in service. Therefore, a proper characterization method is of vital importance to obtain the detailed residual stress distribution. The conventional X-ray diffraction method can only measure the residual stress of near surface but cannot determine the internal bulk stress with nondestructive way. In the present work, a new Short-Wave X-Ray Diffraction (SWXRD) test methodology was utilized, which can evaluate not only the surface but also the internal residual stress of a crystalline material by applying the monochromatic short-wave X-ray of high-energy. The results show that there is a “M” shaped distribution of residual stress of longitudinal direction (LD) in different affected zone. Furthermore, the characterization of residual stress along weld depth direction demonstrates that the middle part of weld joint is subjected to tensile stress while the rest is subjected to compressive stress.

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