Quantitative texture analysis of a hydroxyapatite coatings plasma-sprayed on titanium substrates at different temperatures

2020 ◽  
Vol 86 (12) ◽  
pp. 23-31
Author(s):  
V. F. Shamray ◽  
V. N. Serebryany ◽  
A. S. Kolyanova ◽  
V. I. Kalita ◽  
V. S. Komlev ◽  
...  
Keyword(s):  
Texture Analysis ◽  
Room Temperature ◽  
Volume Fraction ◽  
Rietveld Method ◽  
Orientation Distribution ◽  
Hydroxyapatite Coatings ◽  
Spraying Parameters ◽  
Pole Figures ◽  
Different Temperatures ◽  
Plasma Sprayed

Artificial hydroxyapatite exhibits an excellent biocompatibility with tissues of human body. However, poor mechanical properties of hydroxyapatites and low reliability in wet environments restrict their use. These limitations can be overcome by applying the hydroxyapatite as a coating onto metallic implants. X-ray diffraction analysis (restoration of orientation distribution function from pole figures and the Rietveld method) and scanning electron microscopy have been used to study thick (~330 μm) plasma-sprayed hydroxyapatite coatings. The coatings were deposited onto Ti – 2Al – 1Mn alloy substrates, one of which was held at room temperature (20°C) whereas the other substrate was preheated to 550°C. The texture of the coating deposited on substrate held at room temperature is characterized by the (001)[510] orientation, the volume fraction of which is 0.08, while the coating deposited on preheated substrate has the (001)[410] orientation, the volume fraction of which is 0.10. Results of texture analysis are qualitatively supported by the Rietveld refinement data. The problem of the formation of basal texture in plasma-sprayed hydroxyapatite coatings is discussed in terms of quantitative texture analysis in relation to the differences in the substrate temperature and spraying parameters. It was concluded that the quantitative texture analysis is of importance for deeper understanding the effect of spraying parameters on the formation of hydroxyapatite coatings.

scholarly journals Estimation of Phase Ratio in Bulk, Textured TWIP/TRIP Steels from Pole Figures

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4132
Author(s):  
Marton Benke ◽  
Adrienn Hlavacs ◽  
Ferenc Kristaly ◽  
Mate Sepsi ◽  
Valeria Mertinger
Keyword(s):  
Volume Fraction ◽  
Rietveld Method ◽  
Bragg Reflection ◽  
Phase Ratio ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
Trip Steels ◽  
Pole Figures ◽  
Different Temperatures ◽  
Ε Martensite

The volume fraction of austenite (γ), ε martensite and α′ martensite is of key importance in the research of TWIP/TRIP steels. When mechanical loading is involved, the crystallographic texture also develops, which complicates X-ray diffraction-based phase ratio determination. The problem is more pronounced when only a couple, or only one Bragg-reflection can be measured. A solution for such cases is to determine the ratio of the phases based on the pole distribution function of a selected Bragg-reflection of the present phases. In this manuscript, this method is reconsidered for and applied to non-transmittable bulk specimens for the first time in the reflection mode of XRD pole figure measurements. First, the method was applied to a series of γ–α′ powder mixtures. The results were compared to those obtained by the Rietveld method. Afterwards, the technique was applied to strongly textured, bulk TWIP/TRIP steel specimens which were tensile tested at different temperatures. It was shown that the results of the presented method were close to those of the Rietveld technique in the case of powder mixtures. The results of the tensile-tested steels revealed that the α′ content increases with decreasing test temperatures, and the variation of the α′ ratio correlates very well with the ultimate tensile strength versus the temperature, confirming the contribution of the α′ content to the strength of TWIP/TRIP steels.

scholarly journals Texture Analysis of a Zinc Layer on a Steel Substrate Using Neutron Diffraction

1993 ◽  
Vol 21 (2-3) ◽  
pp. 71-78
Author(s):  
H.-G. Brokmeier
Keyword(s):  
Distribution Function ◽  
Neutron Diffraction ◽  
Texture Analysis ◽  
Orientation Distribution Function ◽  
Steel Substrate ◽  
Orientation Distribution ◽  
Pole Figures ◽  
Iron And Zinc

This paper describes the application of neutron diffraction to investigate the texture of a zinc layer 8 μm in thickness. In a nondestructive way both the texture of the zinc layer as well as the texture of the steel substrate were studied. Therefore, pole figures of iron ((110), (200) and (211)) and of zinc ((0002), (101¯0), (101¯1); and (101¯3)/(112¯0)) were measured; additionally the orientation distribution function of iron and zinc were calculated.

scholarly journals Resolution of Superimposed Diffraction Peaks in Texture Analysis of a YBa2Cu3O7 Polycrystal

1991 ◽  
Vol 13 (2-3) ◽  
pp. 189-197 ◽  
Author(s):  
John S. Kallend ◽  
R. B. Schwarz ◽  
A. D. Rollett
Keyword(s):  
Crystal Structure ◽  
Texture Analysis ◽  
Crystal Orientation ◽  
Orientation Distribution ◽  
Powder Sample ◽  
Oxide Superconductors ◽  
Pole Figures ◽  
Diffraction Peaks ◽  
Near Degeneracy ◽  
Magnetically Aligned

Texture measurements in polycrystalline 123 oxide superconductors are complicated by the superposition of Bragg reflections in the pole figures due to the near degeneracy of the crystal structure. A method is described, based on an extension of the WIMV algorithm, for resolving these superpositions and determining the crystal orientation distribution (OD). The method is exemplified by OD analysis of a magnetically aligned, strongly textured powder sample of YBa2Cu3O7.

Neutron Diffraction Texture Analysis of Grain-Oriented Steel Sheets

2005 ◽  
Vol 105 ◽  
pp. 175-180 ◽  
Author(s):  
Stanislav Vratislav ◽  
Maja Dlouhá ◽  
Ladislav Kalvoda
Keyword(s):  
Neutron Diffraction ◽  
Cold Rolling ◽  
Texture Analysis ◽  
Volume Fraction ◽  
Rolling Direction ◽  
Orthorhombic Symmetry ◽  
Automatic Data ◽  
Cubic Symmetry ◽  
Steel Sheets ◽  
Pole Figures

Our laboratory developed and tested experimental and calculation techniques for quantitative texture analysis based on the ODF combined with the diffraction of thermal neutrons. In our work the texture of the Fe-3%Si sheets was investigated after different stages of their processing, i.e. hot-rolled strips, first cold rolling, first inter-annealing, second cold rolling, second annealing and secondary recrystallisation. The texture experiments were carried out on the KSN-2 diffractometer which is equipped with the TG-1 texture goniometer with automatic data collection for transmission and reflection geometry. TODFND (the cubic symmetry of the crystals and orthorhombic symmetry of the specimen) was used and the ODF values were obtained together with all texture characteristics (pole figures, inverse pole figures, ODF - f (g) values, fibre texture with <110> and <001> axis parallel to rolling direction, parameters of the ideal orientations (HKL)<uvw>, texture index J, volume fraction coefficient f. The comparison of the texture parameters of the six samples with the different technologic history is given and the magnetic anisotropy of all measured samples was determined by means of the quantitative texture analysis (ODF-the matrix Cl nµ) for all samples. Results achieved in our study confirm that the quantitative texture analysis in connection with neutron diffraction can help to improve the technology of the preparation of oriented magnetic steel sheets.

Effects of Spraying Parameters on Phase Formation and Distribution in Plasma-Sprayed Hydroxyapatite Coatings

2000 ◽  
Author(s):  
L. Sun ◽  
C.C. Berndt ◽  
R.S. Lima ◽  
A. Kucuk ◽  
K.A. Khor
Keyword(s):  
Opposite Effect ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Tetracalcium Phosphate ◽  
X Ray ◽  
Impurity Phases ◽  
Hydroxyapatite Coatings ◽  
Spraying Parameters ◽  
Plasma Sprayed ◽  
Spray Dried

Abstract Calcined spray-dried hydroxyapatite (Ca10(PO4)(OH)6; i.e., HA) powders were atmospherically plasma sprayed (APS) using various process parameters. The resulting phases within the coating surface and the interface between the coating and the substrate were analyzed using X-ray diffraction (XRD) methods. This XRD revealed the presence of both amorphous (i.e., amorphous calcium phosphate: ACP) and crystalline phases. The crystalline phases included both HA and some impurity phases from the decomposition of HA, such as tricalcium phosphate (α-TCP and β-TCP), tetracalcium phosphate (TTCP) and calcium oxide (CaO). The crystallinity of HA decreased with increasing spray power and stand-off distance (SOD). The percentage of all impurity phases increased with the spray power. The percentage of both TCP and TTCP decreased with the SOD while the CaO percentage increased. In addition, the percentage of ACP and CaO were higher in the interface than at the surface of the coating while the percentage of TCP and TTCP exhibited the opposite effect.

Improvements in the Quantitative Evaluation of Three-Dimensional Texture. II. The Pole-Figure-Multiplying Method

1995 ◽  
Vol 28 (5) ◽  
pp. 532-533 ◽  
Author(s):  
L.-G. Yu ◽  
H. Guo ◽  
B. C. Hendrix ◽  
K.-W. Xu ◽  
J.-W. He
Keyword(s):  
Distribution Function ◽  
Texture Analysis ◽  
Pole Figure ◽  
Quantitative Evaluation ◽  
Orientation Distribution Function ◽  
Three Dimensional ◽  
Orientation Distribution ◽  
Simple Method ◽  
Pole Figures

A new simple method is proposed for determining the orientation distribution function (ODF) for three-dimensional texture analysis in a polycrystal based on the reality that the accuracy of an ODF is dependent on both the accuracy of each measured pole figure and the number of pole figures.

Phase Transformation Textures in Ti-6Al-4V Alloy

2005 ◽  
Vol 495-497 ◽  
pp. 681-686 ◽  
Author(s):  
Sven C. Vogel ◽  
D. Bhattacharyya ◽  
G.B. Viswanathan ◽  
D.J. Williams ◽  
H.L. Fraser
Keyword(s):  
Orientation Relationship ◽  
Room Temperature ◽  
Volume Fraction ◽  
Turbine Blades ◽  
Large Body ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Transformation Mechanism ◽  
Two Phase ◽  
Crystal Direction

Titanium alloys are widely used in various industrial, domestic, and medical applications such as turbine blades, bicycle frames, knee implants, etc. The two-phase titanium alloy Ti-6Al-4V (wt. percent) is considered to be a workhorse alloy for many applications in these diverse fields. Despite the large body of work on this alloy, the question of the transformation mechanism from the hcp a to the bcc b phase, occurring on heating to temperatures above the a/b transus at ~980°C, is still unresolved. Due to experimental difficulties, it has not yet been clearly determined whether the increase in b volume fraction occurs by fresh nucleation of b crystals within a phase grains or the growth of preexisting b grains. Since the Burgers orientation relationship holds only if the b grains are nucleated within the a grains, the outcome of this question greatly affects texture-modeling efforts for this system. The Burgers orientation relationship predicts that the {0001} crystal direction in a grain of the a phase becomes a {110} crystal direction in a grain of the b phase after the transformation. In this work we present experimental results from in-situ texture measurements performed on the HIPPO neutron diffractometer at LANSCE. Using the combination of time-offlight neutrons and full-pattern Rietveld analysis allowed us to determine the orientation distribution functions of both phases at room temperature, 800°C, 1020°C and again at room temperature. We found strong indications that the b phase indeed grows from grains preexisting at room temperature. Upon re-transformation from b to a we found that the Burgers relationship is followed.

Rietveld texture analysis of Dabie Shan eclogite from TOF neutron diffraction spectra

2001 ◽  
Vol 34 (4) ◽  
pp. 442-453 ◽  
Author(s):  
H.-R. Wenk ◽  
L. Cont ◽  
Y. Xie ◽  
L. Lutterotti ◽  
L. Ratschbacher ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Texture Analysis ◽  
Pole Figure ◽  
Rietveld Method ◽  
Orientation Distribution ◽  
Central China ◽  
Harmonic Method ◽  
Dabie Shan ◽  
Orientation Distributions ◽  
Pulsed Neutron

Orientation distributions of garnet and omphacite in eclogite from the ultra-high pressure Dabie Shan belt in east-central China were determined from neutron diffraction data by the Rietveld method. Diffraction spectra were recorded in 16 sample orientations with seven detectors, with a kappa-geometry texture goniometer at the time-of-flight (TOF) neutron facility at the Intense Pulsed Neutron Source (IPNS). The textures of the two minerals were extracted simultaneously from 16 × 7 = 112 diffraction spectra, covering a large portion of the pole figure. The texture analysis was performed both with the Williams–Imhof–Matthies–Vinel (WIMV) method and the harmonic method, implemented in the program packageMAUD. The incomplete pole-figure coverage introduced artificial oscillations in the case of the harmonic method. The discrete WIMV method produced better results, which illustrate a more or less random orientation distribution for cubic garnet. Apparently elongated grains turned out to be layers of randomly oriented crystals. Monoclinic omphacite displays a sharp texture, with [001] parallel to the lineation direction. The texture data obtained by neutron diffraction were verified with EBSP (electron backscatter pattern) measurements.

scholarly journals Optimization of Texture Measurements—Part II: Further Applications: Optimal Smoothing

1999 ◽  
Vol 33 (1-4) ◽  
pp. 357-363
Author(s):  
V. Luzin
Keyword(s):  
Texture Analysis ◽  
Singular Integrals ◽  
Integral Kernel ◽  
Orientation Distribution ◽  
Quantitative Approach ◽  
Pole Density ◽  
Basic Principles ◽  
Density Data ◽  
Pole Figures ◽  
Optimal Smoothing

In our previous paper (Luzin, 1997. Proc. of Workshop “Neutron Textures and Stress Analysis”) the basic principles of the quantitative approach to optimize the texture measurements were outlined. This paper is the report of advances in this direction.The quantitative approach is used to solve the smoothing problem. Smoothing by singular integrals with an integral kernel used by Nikolayev and Ullemeyer (1996). Proc. of Workshop “Math. Methods of Texture Analysis”, Textures and Microstructures25, 149– 158 is used in this paper. It is shown how the optimal smoothing parameter depends on the grain statistics, i.e. the number of grains in the sample. The algorithm for optimal smoothing of real pole density data (pole figures) is proposed.Also, the application of optimal smoothing for solving the central problem of quantitative texture analysis (QTA), i.e. orientation distribution function (ODF) reproduction, is discussed.

Texture and Structure Study of AZ41 Alloy after ECAP and Annealing

2013 ◽  
Vol 753 ◽  
pp. 469-472 ◽  
Author(s):  
Vladimir N. Serebryany ◽  
Grigory S. Djyakonov ◽  
Gennady A. Salishchev ◽  
Vladimir I. Kopylov ◽  
Sergey V. Dobatkin
Keyword(s):  
Grain Boundaries ◽  
Volume Fraction ◽  
Structural Parameters ◽  
Orientation Distribution ◽  
Structure Study ◽  
Subsequent Annealing ◽  
Angular Pressing ◽  
Pole Figures ◽  
Average Size ◽  
Ebsd Method

Equal channel angular pressing (ECAP) of magnesium alloys dramatically effects the texture and structure of the alloys due to processes of severe plastic deformation and dynamic recrystallization. Changes in texture, structure and tensile properties of AZ41 alloy after ECAP by Bc regime with 4 passes at a temperature of 245° C and subsequent annealing were studied. Evaluation of texture and structure was performed using the orientation distribution function (ODF) restore from the X-ray direct pole figures and the large number of individual orientations measured by the EBSD method. After ECAP the structure of the dynamically recrystallized fine grains with an average size of about 2,9 μm was revealed. The ratio of the volume fraction of low angle grain boundaries (LAGBs) to the high angle grain boundaries (HAGBs) constituted as 1:3. The formation of few basal texture, tilted by 45 ÷ 55 ° to the pressing direction was also found. Subsequent annealing increases the grain size to 10 μm, the fraction of HAGBs - up to 85% and practically does not change the texture type. These changes in structural parameters improve considerably the low-temperature ductility of AZ41 alloy.

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