Real Time Monitoring of the Strain Evolution during Rapid Heat Treatment of Steel Samples by Means of Synchrotron X-Ray Diffraction

2010 ◽  
Vol 638-642 ◽  
pp. 2423-2428 ◽  
Author(s):  
Vladimir Kostov ◽  
Jens Gibmeier ◽  
Stephen Doyle ◽  
Alexander Wanner

An innovative experimental set-up for fast X-ray diffraction analysis on polycrystalline materials has been established at the synchrotron radiation facility ANKA (Karlsruhe, Germany). Key components of the set-up are two fast microstrip line detectors arranged symmetrically around the incident beam in the backscatter region. The capabilities of the set-up are tested by means of in-situ heat treatment experiments on SAE 4140 steel samples. In this feasibility study the heat was introduced by means of either a heating stage or by means of a gas tungsten arc welding torch. It will be shown that the evolution of thermal and elastic lattice strains can be monitored at a sampling rate of up to 4 Hz at a bending-magnet synchrotron beamline. Since the sampling rate may be increased further at a insertion device synchrotron beamline providing higher photon flux, our setup appears to be feasible for monitoring laser treatments in real time.

Author(s):  
Patrick W. DeHaven

X-ray diffraction(XRD) from polycrystalline materials is a powerful structural probe, capable of obtaining information on phase(s), crystallite orientation, average grain size, and residual stress. One problem in the application of XRD to the analysis of semiconductor chips and multi-chip carriers is that there is often the need to obtain information from individual features, which can range in size from several hundred microns on chip carriers to sub-micron on semiconductor devices. Conventional powder diffractometers are designed to irradiate an area of several square millimeters, and cannot be used to examine individual micron-sized features. This need to obtain diffraction information from very small areas has been one of the driving forces behind the development of x-ray microbeam diffraction.The design of a microdiffractometer involves modification of the incident x-ray beam, the sample holder, and the x-ray detector. The incident beam must be focused down to a spot size consistent with the feature to be examined.


Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.


2005 ◽  
Vol 20 (4) ◽  
pp. 1017-1025 ◽  
Author(s):  
Ashutosh S. Gandhi ◽  
Carlos G. Levi

Al2O3–Y2O3 powders were synthesized in the range of 25–55% Y2O3 by reverse coprecipitation of nitrate solutions. All starting powders were amorphous and formed primary yttrium aluminum garnet (YAG) upon crystallization. X-ray diffraction detected only garnet in compositions of 30–40% Y2O3 after heat treatment at 1250 °C. Compositions of 45–55% Y2O3 established a metastable YAG + Y4Al2O9 microstructure. The YAG phase field was metastably extended away from its stoichiometry, as indicated by a systematic increase in lattice parameter with Y2O3 content. Although some Al2O3 enrichment was achieved, YAG appears to tolerate greater off-stoichiometry on the Y2O3-rich side. Possible defect structures accommodating the solubility extension were examined. Phase selection results indicate that compositional inhomogeneity is not the only reason behind the appearance of hexagonal YAlO3, which is frequently reported during YAG synthesis.


MRS Advances ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 563-567 ◽  
Author(s):  
Quentin Altemose ◽  
Katrina Raichle ◽  
Brittani Schnable ◽  
Casey Schwarz ◽  
Myungkoo Kang ◽  
...  

ABSTRACTTransparent optical ZnO–Bi2O3–B2O3 (ZBB) glass-ceramics were created by the melt quenching technique. In this work, a melt of the glass containing stoichiometric ratios of Zn/Bi/B and As was studied. Differential scanning calorimeter (DSC) measurements was used to measure the thermal behavior. VIS/NIR transmission measurements were used to determine the transmission window. X-ray diffraction (XRD) was used to determine crystal phase. In this study, we explore new techniques and report a detailed study of in-situ XRD of the ZBB composition in order to correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase.


2013 ◽  
Vol 212 ◽  
pp. 15-20
Author(s):  
Kazimierz J. Ducki ◽  
Jacek Mendala ◽  
Lilianna Wojtynek

The influence of prolonged ageing on the precipitation process of the secondary phases in an Fe-Ni superalloy of A-286 type has been studied. The samples were subjected to a solution heat treatment at 980°C for 2 h and water quenched, and then aged at temperatures of 715, 750 and 780°C at holding times from 0.5 to 500 h. Structural investigations were conducted using TEM and X-ray diffraction methods. The X-ray phase analyses performed on the isolates were obtained by anodic dissolution of the solid samples. After solution heat treatment the alloy has the structure of twinned austenite with a small amount of undissolved precipitates, such as carbide TiC, carbonitride TiC0.3N0.7, nitride TiN0.3, carbosulfide Ti4C2S2, Laves phase Ni2Si, and boride MoB. The application of ageing causes precipitation processes of γ-Ni3(Al,Ti), G (Ni16Ti6Si7), η (Ni3Ti), β (NiTi) and σ (Cr0.46Mo0.40Si0.14) intermetallic phases, as well as the carbide M23C6. It was found that the main phase precipitating during alloy ageing was the γ intermetallic phase.


2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.


2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Peter Nadazdy ◽  
Jakub Hagara ◽  
Petr Mikulik ◽  
Zdenko Zaprazny ◽  
Dusan Korytar ◽  
...  

A four-bounce monochromator assembly composed of Ge(111) and Ge(220) monolithic channel-cut monochromators with V-shaped channels in a quasi-dispersive configuration is presented. The assembly provides an optimal design in terms of the highest transmittance and photon flux density per detector pixel while maintaining high beam collimation. A monochromator assembly optimized for the highest recorded intensity per detector pixel of a linear detector placed 2.5 m behind the assembly was realized and tested by high-resolution X-ray diffraction and small-angle X-ray scattering measurements using a microfocus X-ray source. Conventional symmetric and asymmetric Ge(220) Bartels monochromators were similarly tested and the results were compared. The new assembly provides a transmittance that is an order of magnitude higher and 2.5 times higher than those provided by the symmetric and asymmetric Bartels monochromators, respectively, while the output beam divergence is twice that of the asymmetric Bartels monochromator. These results demonstrate the advantage of the proposed monochromator assembly in cases where the resolution can be partially sacrificed in favour of higher transmittance while still maintaining high beam collimation. Weakly scattering samples such as nanostructures are an example. A general advantage of the new monochromator is a significant reduction in the exposure time required to collect usable experimental data. A comparison of the theoretical and experimental results also reveals the current limitations of the technology of polishing hard-to-reach surfaces in X-ray crystal optics.


Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 311 ◽  
Author(s):  
Carlotta Giacobbe ◽  
Jonathan Wright ◽  
Dario Di Giuseppe ◽  
Alessandro Zoboli ◽  
Mauro Zapparoli ◽  
...  

Nowadays, due to the adverse health effects associated with exposure to asbestos, its removal and thermal inertization has become one of the most promising ways for reducing waste risk management. Despite all the advances in structure analysis of fibers and characterization, some problems still remain that are very hard to solve. One challenge is the structure analysis of natural micro- and nano-crystalline samples, which do not form crystals large enough for single-crystal X-ray diffraction (SC-XRD), and their analysis is often hampered by reflection overlap and the coexistence of multiple fibres linked together. In this paper, we have used nano-focused synchrotron X-rays to refine the crystal structure of a micrometric tremolite fibres from Val d’Ala, Turin (Italy) after various heat treatment. The structure of the original fibre and after heating to 800 °C show minor differences, while the fibre that was heated at 1000 °C is recrystallized into pyroxene phases and cristobalite.


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