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.

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 Effect of the γ→ε Phase Transition on Transformation-Induced Plasticity (TRIP) of Nickel-Free High Nitrogen Steel at Low Temperatures

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 710
Author(s):  
Natalia Narkevich ◽  
Yevgeny Deryugin ◽  
Yury Mironov
Keyword(s):  
Volume Fraction ◽  
Tensile Load ◽  
X Ray Diffraction ◽  
High Nitrogen Steel ◽  
Transformation Induced Plasticity ◽  
X Ray ◽  
Root Cause ◽  
Nitrogen Steel ◽  
Ε Phase ◽  
Ε Martensite

The deformation behavior, mechanical properties, and microstructure of Fe-Cr-Mn-0.53%N austenitic stainless steel were studied at a temperature range of 77 up to 293 K. The dynamics of the steel elongation were non-monotonic with a maximum at 240–273 K, when peaks of both static atom displacements from their equilibrium positions in austenite and residual stresses in the tensile load direction were observed. The results of X-ray diffraction analysis confirmed that the only stress-induced γ→ε-martensite transformation occurred upon deformation (no traces of the γ→α′ one was found). In this case, the volume fraction of ε-martensite was about 2–3%. These transformation-induced plasticity (TRIP) patterns were discussed in terms of changes in the phase composition of steel as the root cause.

Preparation and Property of Al87Ce3Ni8.5Mn1.5 Nanophase Amorphous Composites

2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Phase ◽  
Volume Fraction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.

scholarly journals Influence of Temperature on Stress Distribution in Bainitic Steels - Application to 16 MND5-A508 Pressure Vessel Steel

2011 ◽  
Vol 681 ◽  
pp. 243-248 ◽  
Author(s):  
Razane Ouahab ◽  
Raphaël Pesci ◽  
Sophie Berveiller ◽  
Etienne Patoor
Keyword(s):  
Volume Fraction ◽  
Pressure Vessel Steel ◽  
X Ray Diffraction ◽  
In Situ Tests ◽  
Vessel Steel ◽  
Bainitic Steels ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Very High

In this study, the internal stress evolution of the ferrite phase of 16MND5-A508 has been determined using X-Ray Diffraction (XRD). The results of in situ tests combined with XRD analyses and performed at different temperatures (-150°C and 22°C) exhibit a difference of about 200MPa between the macroscopic stress and the ferrite one. The stress state in the cementite is determined by a mixture law; it reaches very high values up to 9000MPa. These results highlight the need to analyze the stress directly in the cementite phase by using appropriate tools, since its volume fraction does not allow it using XRD.

Magnetic Hardening of Mechanichally Alloyed SmFe11−xCoxTi

1999 ◽  
Vol 581 ◽  
Author(s):  
L. Bessais ◽  
C. Djega-Mariadassou
Keyword(s):  
Heat Treatment ◽  
Rietveld Method ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Different Temperatures ◽  
Magnetic Hardening ◽  
Property Changes ◽  
Nanocrystalline Phases

ABSTRACTMechanical alloying of ternary SmFe11−xCoxTi (x = 0, 0.5, 1, 1.5, 2) alloys was carried out under an Ar atmosphere. Milled samples were annealed for 30 min in a vacuum at different temperatures Ta from 650 °C to 1150 °C. The effects of heat treatment, on structure and magnetic property changes, have been investigated by means of x-ray diffraction using the Rietveld method, Mössbauer spectroscopy and differential sample magnetometer. Tetragonal ThMn12-type structure is observed for samples annealed at Ta > 900 °C. For 650<Ta<800 °C the TbCu7 type phase was identified as the major phase. Between these two regions a mixture of TbCu7 and ThMn12-type nanocrystalline phases is obtained with a maximum of the coercive field Hc (Hc > 5kOe). The Mössbauer spectra relative to the hexagonal phase show sextuplets broadened by the statistical occupancies of the iron sites. An enhancement of the magnetic properties results from the Co substitution.

Investigation of Deformation Induced Martensitic Transformation during Incremental Forming of 304 Stainless Steel Wires

2015 ◽  
Vol 651-653 ◽  
pp. 645-650 ◽  
Author(s):  
Bernd Kuhfuss ◽  
Eric Moumi ◽  
Brigitte Clausen ◽  
Jeremy Epp ◽  
Bernd Koehler
Keyword(s):  
Volume Fraction ◽  
Processing Parameters ◽  
304 Stainless Steel ◽  
Strain Rates ◽  
X Ray Diffraction ◽  
Forming Process ◽  
Cold Forming ◽  
X Ray ◽  
Steel Wires ◽  
Different Temperatures

Wires with 1 mm initial diameter have been reduced between 10 and 64 percent at different temperatures and strain rates by infeed rotary swaging, which is an incremental cold forming process mainly used for rods and pipes. The volume fraction of martensite in the deformed wires has been determined by X-Ray diffraction and by magnetic induction for different processing parameters. Measurements show that for already small percentage of reduction, martensite is present in the wires and its amount changes with the strain rate and temperature. While for smaller strain rates at room temperature the formation of martensite is promoted, it is restrained for higher strain rates and higher temperatures. Results also reveal that the martensite distribution in the sample is inhomogeneous. Further investigations have been made to analyze the microstructure by optical microscopy and to determine mechanical properties by tensile testing.

scholarly journals Relationship between the Tensile Properties and Damping Capacity of Fe-22%Mn-12%Cr-4%Co-3%Ni-2%Si Alloys by Fatigue Stress

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7160
Author(s):  
Jae-Hwan Kim ◽  
Myong-Soo Lee ◽  
Jong-Sig Kim
Keyword(s):  
Tensile Properties ◽  
Volume Fraction ◽  
Damping Capacity ◽  
General Tendency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fatigue Stress ◽  
Ε Martensite ◽  
The Relationship ◽  
Specific Orientation

The relationship between the tensile properties and damping capacity of fatigue-damaged Fe-22%Mn-12%Cr-4%Co-3%Ni-2%Si alloy under various magnitudes of fatigue stress was investigated. Analytical results show that α′- and ε-martensite were formed due to fatigue stress. The formed α′- and ε-martensite followed a specific orientation and surface relief and intersected with each other. TEM observation and pattern analysis reveal that both α′- and ε-martensites formed on the austenite. As a result of X-ray diffraction, with an increase in fatigue stress, the volume fractions of α′- and ε-martensite were increased, and the increasing rate of the volume fraction of α′-martensite was higher than that of the ε-martensite. As the fatigue stress increased, the tensile strength and damping capacity increased, but the elongation decreased. Besides, as the strength increased and the elongation decreased, the damping capacity decreased. This result is inconsistent with the general tendency for metals but similar to that of alloys undergoing deformation-induced martensite transformation.

STUDY OF ION BEAM SYNTHESIZED YSi2-x LAYERS

2010 ◽  
Vol 09 (06) ◽  
pp. 549-552
Author(s):  
AYACHE RACHID ◽  
BOUABELLOU ABDERRAHMANE ◽  
EICHHORN FRANK
Keyword(s):  
Electron Microscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Pole Figures ◽  
Different Temperatures ◽  
Scanning Electron

The processes in the synthesis of a thin layer of hexagonal YSi 2-x phase on a single-crystal Si (111) substrate by implantation of 195 keV Y ions with a dose of 2 × 1017 Y +/ cm 2 at 300°C followed by annealing in an N2 atmosphere at different temperatures for 1 h are investigated. The characterization of the as-implanted and annealed samples is performed using Rutherford backscattering spectrometry (RBS) and X-ray diffraction (XRD) pole figures. Scanning electron microscopy (SEM) was used to view the surface topography. The results show that the orientation relationship between the YSi 2-x layer and Si substrate is YSi 2-x(0001)// Si (111) and YSi 2-x[11–20]// Si [110].

Combustion Synthesis of Cu1-xNixCr2O4 Spinel for Catalytic Applications

2005 ◽  
Vol 498-499 ◽  
pp. 663-668 ◽  
Author(s):  
P.M. Pimentel ◽  
M.F. Ginani ◽  
Antonio Eduardo Martinelli ◽  
D.M.A. Melo ◽  
A.M. Garrido Pedrosa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Catalytic Combustion ◽  
Fine Particles ◽  
Particle Morphology ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Heterogeneous Processes ◽  
Different Temperatures ◽  
Cost Efficient

Transition-metal spinels are efficient catalysts in a number of heterogeneous processes, such as CO oxidation, catalytic combustion of hydrocarbons and oxychlorination of methane. The properties of catalytic materials are highly dependent on the synthesis route. Spinels are often produced at high temperatures by the calcination of precursors such as powder mixtures, slurries or resins. Combustion synthesis is a cost-efficient method used to produce homogeneous and fine particles with high reproducibility. Cu0.8Ni0.2Cr2O4 spinel was obtained by the combustion of metallic nitrates using urea as fuel. The resulting powders were calcinated at different temperatures and characterized by thermogravimetric and particle size analyses, X ray diffraction, and scanning electron microscopy. The effect of urea on the control of the process and particle morphology was investigated. The results revealed the formation of porous powders with increasing crystallinity as the calcination temperature increased. Crystallization of spinel started at 700 oC.

scholarly journals Role of the extra Fe in K2−xFe4+ySe5 superconductors

2019 ◽  
Vol 116 (4) ◽  
pp. 1104-1109 ◽  
Author(s):  
Chih-Han Wang ◽  
Chih-Chien Lee ◽  
Gwo-Tzong Huang ◽  
Jie-Yu Yang ◽  
Ming-Jye Wang ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Parent Compound ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Different Temperatures ◽  
Two Phases ◽  
Best Fit

The exact superconducting phase of K2−xFe4+ySe5 has so far not been conclusively decided since its discovery due to its intrinsic multiphase in early material. In an attempt to resolve this mystery, we have carried out systematic structural studies on a set of well-controlled samples with exact chemical stoichiometry K2−xFe4+xSe5 (x = 0–0.3) that are heat-treated at different temperatures. Using high-resolution synchrotron radiation X-ray diffraction, our investigations have determined the superconducting transition by focusing on the detailed temperature evolution of the crystalline phases. Our results show that superconductivity appears only in those samples that have been treated at high-enough temperature and then quenched to room temperature. The volume fraction of superconducting transition strongly depends on the annealing temperature used. The most striking result is the observation of a clear contrast in crystalline phase between the nonsuperconducting parent compound K2Fe4Se5 and the superconducting K2−xFe4+ySe5 samples. The X-ray diffraction patterned can be well indexed to the phase with I4/m symmetry in all temperatures investigated. However, we need two phases with similar I4/m symmetry but different parameters to best fit the data at a temperature below the Fe vacancy order temperature. The results strongly suggest that superconductivity in K2−xFe4+ySe5 critically depends on the occupation of Fe atoms on the originally empty 4d site.

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