Portable X-ray Diffractometer Research Articles

Influence of Rebar Strength, Pre-treatment, and Measurement Method on Residual Stress Measurement using Portable X-ray Diffractometer

Influence of Rebar Strength, Pre-treatment, and Measurement Method on Residual Stress Measurement using Portable X-ray Diffractometer

Investigation of Surface Residual Stress for Medium Carbon Steel Quenched by YAG Laser with Extended Cycloidal Motion

This study investigated the surface residual stress for AISI 1045 steel quenched by a YAG laser. A coaxial laser spindle was installed on a CNC machine for the experiment. The laser motion was arranged to follow the path of an extended cycloid which widened the quenching area on the steel surface. Both the temperature distribution and the residual stresses were measured by thermocouples and a portable X-ray diffractometer, respectively. When the temperature distribution was cooled down near the value of the room temperature, the residual stresses were then measured after the laser quenching process. The diffractometer used a single exposure of X-ray with a two-dimensional detector to calculate the Debye–Scherrer ring (D-S ring) for the determination of the normal and shear stresses. Different laser powers were exploited for the measurement of residual stresses, including 500, 600, 700, and 900 watts. In addition to the experiment, an analytic model for the investigation of residual stresses was built by the finite element analysis for which MSC Marc was used. The assumption for the FEA was that the laser spot had a circular shape of uniform energy distribution and the thermal–elastic–plastic model was applied to the simulation for the laser quenching process. The analytic and experimental results for the surface residual stresses had excellent consistency with a maximum difference of 10.5% from the normal stresses. The numerical results for the residual stresses also revealed that the normal stresses were compressive for the laser-quenching treatment and the shear stress could be neglected compared to the normal stress.

Phenomenological wear model of case-hardened 20MnCr5 under cyclic line rolling contact

Tribo-machineries employ machine elements, such as discs and gears, which are frequently subjected to Hertzian loads that cause their mechanical failure. Case hardening is a popular method that ensures better productivity and performance of such elements compared to its untreated variants. This paper presents a wear and fatigue model for case hardened steels under Hertzian loads in line contact. Steel discs with different case hardening depths were tested using a three-disc testing machine, and the samples were analyzed using optical microscopy, SEM and a portable X-ray diffractometer. The influence of type of contact, case hardening depths, normal force (contact stress) and slip conditions on the damage process are investigated in detail. It was found that the hardening layer should be adapted to the load, since a too large hardening depth means a shorter service life due to higher residual stresses gradients. The transferability of results to increase the service life of real-life components is an essential component of this work.

ОПРЕДЕЛЕНИЕ ЦЕЛЕСООБРАЗНОСТИ ГРАВИТАЦИОННОГО ОБОГАЩЕНИЯ РУДЫ МЕСТОРОЖДЕНИЯ «ДЖАМГЫР»

PURPOSE. The paper studies the material composition of the ore from the Jamgyr deposit located in the Chatkal region of the Jalal-Abad district of the Kyrgyz Republic and determines the expediency of its gravity concentration. The ore belongs to the quartz low sulfide type. Its main valuable component is gold, the content of which averages 8.5 g/t. METHODS. Complex mineralogical analysis was performed using X-ray phase, optical and microscopic analyzes. Sulphide minerals and gold were studied using the method of selective dissolution of natural minerals. X-ray phase analysis was carried out on a portable X-ray diffractometer D2 PHASER (CuKa) of Bruker AXS design in the range of 20 angles from 5 to 80°. The obtained diffractograms were processed in the DIFFRAC.EVA program. A qualitative X-ray phase analysis was performed via comparison of standards (ICDD PDF-2) and diffractograms. A semiquantitative analysis of the sample was carried out using the DIFFRAC.TOPAS program according to Rietveld method. The content of gold was determined on the atomic absorption multielement spectrometer AGEP-0,1 by the assay atomic absorption analysis. RESULTS AND THEIR DISCUSSION. Having studied the morphology of particles of free gold, we have found that the shape of coarse gold is mainly dendritic, small-size gold has the shape of a drop in pyrite. The data on the granulometric distribution of gold show that the percentage of coarse gold is about 70%. The phase analysis data show that the percentage of free gold is 64.37%. The ore study has allowed to substantiate the use of gravity concentration through the GRG test at a hydraulic pressure of 25-12 kPa, ore feed rates from 1000 g/min to 400 g/min, stage-by-stage reduction in size from 100% of 85 μm to 80% of 75 μm. The technique of performing the stage-by-stage gravity concentration conducted in three stages on Knelson concentrator is given and the GRG test determination diagram is presented. The results of each stage and the total result of the GRG test are provided. According to the GRG test result 19.86% of free gold is extracted at the first stage, 35.83% - at the second stage, and 17.65% - at the third stage. The total recovery is 73.34%. CONCLUSIONS. The morphology and release of gold on the concentrates obtained by gravitation on a centrifugal separator are studied. The degree of gold release is determined as well as the gold grain size in I, II, III stage concentrates and relative amounts of free gold grains. The final determination is given to the main shape of gold grains: it is either dendritic or flake. It is also noted that stage-by-stage decrease in the grind size causes changes in the gold grain shape: the particles of isometric forms are expanded into flat grains.

Analysis of residual stress in subsurface layers after precision hard machining of forging tools

This paper is focused on analysis of residual stress of functional surfaces and subsurface layers created by precision technologies of hard machining for progressive constructional materials of forging tools. Methods of experiments are oriented on monitoring of residual stress in surface which is created by hard turning (roughing and finishing operations). Subsequently these surfaces were etched in thin layers by electro-chemical polishing. The residual stress was monitored in each etched layer. The measuring was executed by portable X-ray diffractometer for detection of residual stress and structural phases. The results significantly indicate rise and distribution of residual stress in surface and subsurface layers and their impact on functional properties of surface integrity.

Experimental results on the irradiation of nuclear fusion relevant materials at the dense plasma focus ‘Bora’ device

Samples of materials counted as perspective ones for use in the first-wall and construction elements in nuclear fusion reactors (FRs) with magnetic and inertial plasma confinement (W, Ti, Al, low-activated ferritic steel ‘Eurofer’ and some alloys) were irradiated in the dense plasma focus (DPF) device ‘Bora’ having a bank energy of ⩽5 kJ. The device generates hot dense (T ∼ 1 keV, n ∼ 1019 cm−3) deuterium plasma, powerful plasma streams (v ∼ 3 × 107 cm s−1) and fast (E ∼ 0.1 … 1.0 MeV) deuterons of power flux densities q up to 1010 and 1012 W cm−2 correspondingly. ‘Damage factor’ F = q × τ0.5 ensures an opportunity to simulate radiation loads (predictable for both reactors types) by the plasma/ion streams, which have the same nature and namely those parameters as expected in the FR modules. Before and after irradiation we provided investigations of our samples by means of a number of analytical techniques. Among them we used optical and scanning electron microscopy to understand character and parameters of damageability of the surface layers of the samples. Atomic force microscopy was applied to measure roughness of the surface after irradiation. These characteristics are quite important for understanding mechanisms and values of dust production in FR that may relate to tritium retention and emergency situations in FR facilities. We also applied two new techniques. For the surface we elaborated the portable x-ray diffractometer that combines x-ray single photon detection with high spectroscopic and angular resolutions. For bulk damageability investigations we applied an x-ray microCT system where x-rays were produced by a Hamamatsu microfocus source (150 kV, 500 µA, 5 µm minimum focal spot size). The detector was a Hamamatsu CMOS flat panel coupled to a fibre optic plate under the GOS scintillator. The reconstruction of three-dimensional data was run with Cobra 7.4 and DIGIX CT software while VG Studio Max 2.1, and Amira 5.3 were used for segmentation and rendering. We have also provided numerical simulation of the fast ion beam action. The paper contains results on the investigations of modifications of the elemental contents, structure and properties of the materials.

Physical processes taking place in dense plasma focus devices at the interaction of hot plasma and fast ion streams with materials under test

The dense plasma focus (DPF) device represents a source of powerful streams of penetrating radiations (hot plasma, fast electron and ion beams, x-rays and neutrons) of ns-scale pulse durations. Power flux densities of the radiation types may reach in certain cases the values up to 1013 W cm − 2. They are widely used at present time in more than 30 labs in the world in the field of radiation material science. Areas of their implementations are testing of the materials perspective for use in modern fusion reactors (FR) of both types, modification of surface layers with an aim of improvements their properties, production of some nanostructures on their surface, and so on. To use a DPF correctly in these applications it is important to understand the mechanisms of generation of the above-mentioned radiations, their dynamics inside and outside of the pinch and processes of interaction of these streams with targets. In this paper, the most important issues on the above matter we discuss in relation to the cumulative hot plasma stream and the beam of fast ions with illustration of experimental results obtained at four DPF devices ranged in the limits of bank energies from 1 kJ to 1 MJ. Among them mechanisms of a jet formation, a current abruption phenomenon, a super-Alfven ion beam propagation inside and outside of DPF plasma, generation of secondary plasma and formation of shock waves in plasma and inside a solid-state target, etc. Nanosecond time-resolved techniques (electric probes, laser interferometry, frame self-luminescent imaging, x-ray/neutron probes, etc) give an opportunity to investigate the above-mentioned events and to observe the process of interaction of the radiation types with targets. After irradiation, we analyzed the specimens by contemporary instrumentation: optical and scanning electron microscopy, local x-ray spectral and structure analysis, atomic force microscopy, the portable x-ray diffractometer that combines x-ray single photon detection with high spectroscopic and angular resolutions, an x-ray microCT system with Cobra 7.4 and DIGIX CT software, microhardness measurements, etc. Some results in this area are presented.

INVESTIGATION OF RESIDUAL STRESSES IN WELDED PIPES

The problem of residual stress distribution in welded tubes is paid a lot attention in recent years because of it is the one of the fracture reason of welded tubes both in production process and in service of products made of them. Since the plastic forming process is performed in cold condition the residual stress appearance (σrs ) in welded tubes is found in the every operation of production process. In this regard it is important to carry out the experimental investigations that make possible the determination of the residual stress nature in the formable workpiece using modern nondestructive methods. This article describes the experimental results of residual stress measurement in the different points around circumference of the outer surface of both small-diameter and large-diameter tubes with the application of portable X-ray diffractometer “DRP-RIKOR” based on X-ray diffraction method.

Long-Term Corrosion of 2,000-Year-Old Ancient Iron Sword

ABSTRACTAn ancient iron sword (ca 2,000 year old) excavated from Ohtake-nishi archaeological site in Osaka Prefecture, is one of the oldest cast iron swords in Japan. Because of a good state of preservation, such as the sharply-defined “Shinogi” (the longitudinal ridge) on the surface, we studied relationship between the burial environment and corrosion behavior. As environmental conditions, we investigated groundwater chemistry and corrosion rate with iron probe monitor, etc. Regarding corrosion state, we analyzed corrosion depths with an X-ray computed tomography and corrosion products with a portable X-ray diffractometer equipped with X-ray fluorescence spectrometer. As results, we found that the redox potential and dissolved oxygen level as environmental conditions were very low, and that the corrosion rate (7.5×10-4 mm/y) evaluated from measured corrosion depths was smaller than the probe corrosion rate (3.2–5.2×10-2 mm/y) by two orders of magnitude. The results suggested that the corrosion layer of siderite formed on the iron sword surface inhibited corrosion reaction.

Studies of Advanced Technologies Used in the Manufacture of Products from Aluminium Alloys

Studies of Advanced Technologies Used in the Manufacture of Products from Aluminium Alloys The test stands already put in operation and still under development, installed in the Light Metals Division Skawina of the Institute of Non-Ferrous Metals in Gliwice are described. The presentation includes 5MN horizontal direct-indirect extrusion press, 2,5MN vertical forging press, "MeltechConfex MC-260" device for continuous rotary extrusion process, "Melt-Spinning" plant for casting of thin strips, melting-casting plant for Mg alloy billets, heat treatment line, and new testing equipment, including Instron 5582 100 kN and Instron 600DX 600 kN testing machines with attachments for tests carried out at low and high temperatures, automatic hardness tester for HB, HV and HRC hardness measurements, portable X-ray diffractometer for measurement of internal stresses, optical emission spectrometer with channels for the analysis of aluminium and magnesium alloys, STEM 200kV transmission electron microscope, and apparatus for hydrogen content measurement in the solid state. Based on the experimental potential and apparatus available, present research opportunities were discussed and modern trends in the advanced technology of Al and Mg alloys fabrication were outlined.

In situ X-ray analytical study on the alteration process of iron oxide layers at the railhead surface while under railway traffic

This paper describes an experimental investigation of in situ X-ray diffraction analysis of iron oxides on the railhead surface, which have an influence on various wheel/rail rolling contact phenomena, e.g. the adhesion between wheels and rails, which can cause rail corrugations. The X-ray analysis using portable X-ray diffractometer installing XRF called “XRDF” was carried out for the preliminary laboratory experiment and the field test. For the laboratory experiment, the rail specimen samples on which rust was generated by scattering salt water mist and moisture vapor alternately were analyzed. The different rust types generated under the different environmental conditions were identified. For the field test, XRDF analysis was applied to the corroded test rail after the test vehicle passed over it several times. As a result, it can be concluded that the decreased proportion of rusts due to passage of the vehicle depends on the track alignment, the location where rails are installed, and the positions across the rail head such as top of rail in tangent track or gauge corner of the high rail in curved track, and also depends on the vehicle running conditions, i.e. free-rolling, driving or braking. Finally, we confirmed the effectiveness of applying XRDF analysis to track site measurements to obtain some important suggestions for understanding the wheel/rail rolling contact phenomena on which rail surface substances have great influence.

Portable X-ray diffractometer equipped with XRF for archaeometry

A portable X-ray diffractometer equipped with an X-ray fluorescence spectrometer was improved so as to get a diffraction pattern and a fluorescence spectrum simultaneously in air from one and the same small area on a specimen. Here, diffraction experiments were performed in two modes, i.e. an angle rotation mode and an energy dispersive mode. In the latter a diffraction pattern and a fluorescence spectrum were simultaneously recorded in a short time, 100 s or less, on one display. The diffractometer was tested in the field to confirm its performance. Targets chosen for this purpose were a bronze mirror from the Eastern Han Dynasty (25–220), and a stupa and its pedestal which are part of the painted statue of “Tamonten holding a stupa” from the Heian Period (794–1192), enshrined in the Engyouji temple founded in 996. The bronze mirror was identified as a product of the Han Dynasty from its chemical composition and the existence of the δ phase in the Cu–Sn alloy. The stupa and its pedestal were decorated with gold powder and gold leaf, respectively. From the XRF data of the pedestal, the underlying layer of gold leaf seems to have been painted with emerald green.