scholarly journals Change in matrix saturation with alloying elements at primary thermocyclic processing of 44NKhTYu alloy

2021 ◽  
Vol 63 (11-12) ◽  
pp. 965-966
Author(s):  
N. V. Red’kina

The total solubility of alloying elements (chromium, titanium, aluminum) in the iron-nickel matrix (Fe – Ni) of 44NKhTYu alloy, depending on the number of cycles, does not occur during primary thermocycling processing (TCP). This is evidenced by the main replicas of the matrix with (111) reflection plane indexes of the samples X-ray images under the studied modes of thermocyclic processing. The maximum solubility of alloying elements is achieved only at total quenching. Special attention should be paid to the third and fourth cycles in the further study of TCP changing the cooling rate in these cycles due to the cooling medium, since with an increase in the number of cycles in the primary TCP, significant changes do not occur.

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 874
Author(s):  
Andrey A. Tsarkov ◽  
Vladislav Yu. Zadorozhnyy ◽  
Alexey N. Solonin ◽  
Dmitri V. Louzguine-Luzgin

High-strength crystalline/amorphous composites materials based on (Ti-Ni)-(Cu-Zr) system were developed. The optimal concentrations of additional alloying elements Al, Fe, and Cr were obtained. Structural investigations were carried out using X-ray diffraction equipment (XRD) and scanning electron microscope (SEM) with an energy-dispersive X-ray module (EDX). It was found that additives of aluminum and chromium up to 5 at% dissolve well into the solid matrix solution of the NiTi phase. At a concentration of 5 at%, the precipitation of the unfavorable NiTi2 phase occurs, which, as a result, leads to a dramatic decrease in ductility. Iron dissolves very well in the solid solution of the matrix phase due to chemical affinity with nickel. The addition of iron does not cause the precipitation of the NiTi2 phase in the concentration range of 0–8 at%, but with an increase in concentration, this leads to a decrease in the mechanical properties of the alloy. The mechanical behavior of alloys was studied in compression test conditions on a universal testing machine. The developed alloys have a good combination of strength and ductility due to their dual-phase structure. It was shown that additional alloying elements lead to a complete suppression of the martensitic transformation in the alloys.


2019 ◽  
Vol 38 (2019) ◽  
pp. 498-504 ◽  
Author(s):  
Tianhua Ju ◽  
Xueyong Ding ◽  
Yingyi Zhang ◽  
Xiangkui Chen ◽  
Weiliang Chen ◽  
...  

AbstractThe partition behavior of alloying elements between the γ’ and γ phases in Nickel-based alloys was investigated by using infinite dilution activity coefficient and activity interaction parameter. The results showed that the preferential partition behavior of elements in the γ’ and γ phases is related to its infinite dilution activity coefficient (\ln \gamma _i^0). When \ln \gamma _i^0 \ll 0, the element i has a strong tendency to partition in the γ’ phase; When \ln \gamma _i^0 approaches to zero, the element i has preferentially partition to the matrix γ phase. In addition, the partition behavior of element i in the γ’ and γ phases is also affected by the third element j in Nickel-based alloys, and this effect can be distinguished by the sign of the second-order activity interaction parameter \rho _i^{ij}.


Author(s):  
H.J. Dudek

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S


Author(s):  
J.Y. Laval

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.


Author(s):  
C.M. Sung ◽  
K.J. Ostreicher ◽  
M.L. Huckabee ◽  
S.T. Buljan

A series of binary oxides and SiC whisker reinforced composites both having a matrix composed of an α-(Al, R)2O3 solid solution (R: rare earth) have been studied by analytical electron microscopy (AEM). The mechanical properties of the composites as well as crystal structure, composition, and defects of both second phases and the matrix were investigated. The formation of various second phases, e.g. garnet, β-Alumina, or perovskite structures in the binary Al2O3-R2O3 and the ternary Al2O3-R2O3-SiC(w) systems are discussed.Sections of the materials having thicknesses of 100 μm - 300 μm were first diamond core drilled. The discs were then polished and dimpled. The final step was ion milling with Ar+ until breakthrough occurred. Samples prepared in this manner were then analyzed using the Philips EM400T AEM. The low-Z energy dispersive X-ray spectroscopy (EDXS) data were obtained and correlated with convergent beam electron diffraction (CBED) patterns to identify phase compositions and structures. The following EDXS parameters were maintained in the analyzed areas: accelerating voltage of 120 keV, sample tilt of 12° and 20% dead time.


Author(s):  
Richard B. Mott ◽  
John J. Friel ◽  
Charles G. Waldman

X-rays are emitted from a relatively large volume in bulk samples, limiting the smallest features which are visible in X-ray maps. Beam spreading also hampers attempts to make geometric measurements of features based on their boundaries in X-ray maps. This has prompted recent interest in using low voltages, and consequently mapping L or M lines, in order to minimize the blurring of the maps.An alternative strategy draws on the extensive work in image restoration (deblurring) developed in space science and astronomy since the 1960s. A recent example is the restoration of images from the Hubble Space Telescope prior to its new optics. Extensive literature exists on the theory of image restoration. The simplest case and its correspondence with X-ray mapping parameters is shown in Figures 1 and 2.Using pixels much smaller than the X-ray volume, a small object of differing composition from the matrix generates a broad, low response. This shape corresponds to the point spread function (PSF). The observed X-ray map can be modeled as an “ideal” map, with an X-ray volume of zero, convolved with the PSF. Figure 2a shows the 1-dimensional case of a line profile across a thin layer. Figure 2b shows an idealized noise-free profile which is then convolved with the PSF to give the blurred profile of Figure 2c.


1989 ◽  
Vol 28 (04) ◽  
pp. 124-128 ◽  
Author(s):  
J. Spitz ◽  
N. Clemenz ◽  
K. Tittel ◽  
H. Weigand

In addition to its established oncological indications the sensitivity of bone scintigraphy is of steadily increasing significance in traumatology. Inactivity- induced osteoporosis plays a major role during the immobilization period in the plaster cast. In the region of the joints remodelling intensity may reach such a high level that the non-injured bone shows a higher rate of accumulation than the fracture. This process already begins between the third and fourth week of immobilization. The highest uptake is found after fracture of the scaphoid bone at the end of twelve weeks of immobilization. Control scintigraphies at intervals of several days are indicated to differentiate between various clinical conditions (pseudoarthrosis, activated osteoarthrosis, algodystrophy in case of doubtful x-ray results).


Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Valérie Laperche ◽  
Bruno Lemière

Portable X-ray fluorescence spectroscopy is now widely used in almost any field of geoscience. Handheld XRF analysers are easy to use, and results are available in almost real time anywhere. However, the results do not always match laboratory analyses, and this may deter users. Rather than analytical issues, the bias often results from sample preparation differences. Instrument setup and analysis conditions need to be fully understood to avoid reporting erroneous results. The technique’s limitations must be kept in mind. We describe a number of issues and potential pitfalls observed from our experience and described in the literature. This includes the analytical mode and parameters; protective films; sample geometry and density, especially for light elements; analytical interferences between elements; physical effects of the matrix and sample condition, and more. Nevertheless, portable X-ray fluorescence spectroscopy (pXRF) results gathered with sufficient care by experienced users are both precise and reliable, if not fully accurate, and they can constitute robust data sets. Rather than being a substitute for laboratory analyses, pXRF measurements are a valuable complement to those. pXRF improves the quality and relevance of laboratory data sets.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Mingchen Zou ◽  
Haotian Wu ◽  
Shuangquan Yao ◽  
Dong Ren ◽  
Song Liu ◽  
...  

Abstract Background This study was done to observe the incidence of Osteo-line on the femur neck and to explore the clinical application of Osteo-line in osteotomy. Methods Eighty-nine adult femur specimens were selected to observe the incidence of Osteo-line on the femur neck. From August 2015 to January 2019, a total of 278 patients who completed unilateral hip arthroplasty at the Third Hospital of Hebei Medical University were retrospectively included. Patients who accepted osteotomy via Osteo-line on the femur neck were defined as the experimental group (n = 139), and patients who accepted osteotomy via traditional method (The femoral distance 1.5 cm above the trochanter was retained for osteotomy by visual inspection.) were defined as the control group (n = 139). According to the postoperative pelvic X-ray, Photoshop was used to evaluate the leg length discrepancy (LLD) by the CFR-T-LT method. Results Among the 89 specimens, the incidence of anterior Osteo-line was 75.28%, and the incidence of posterior Osteo-line was 100%. According to the clinical application results, the incidence of anterior Osteo-line on the femur neck was 80%, and the incidence of posterior Osteo-line was 100%. The Osteo-line was clearer than those on the femoral specimens. Twenty-six cases had LLD greater than 1 cm (9.29%), including 2 cases in the experimental group and 24 cases in the control group. The average postoperative LLD in the experimental group (0.19 ± 0.38 mm) was significantly shorter than in the control group (0.54 ± 0.51 mm)(P = 0.005). Conclusion The incidence of Osteo-line on the femur neck was high, and patients who accepted osteotomy via Osteo-line on the femur neck can achieve shorter postoperative LLD than the control group.


2006 ◽  
Vol 510-511 ◽  
pp. 358-361
Author(s):  
Won Yong Kim ◽  
Han Sol Kim ◽  
In Dong Yeo ◽  
Mok Soon Kim

We report on advanced Ni3Al based high temperature structural alloys with refractory alloying elements such as Zr and Mo to be apllied in the fields of die-casting and high temperature press forming as die materials. The duplex microstructure consisting of L12 structured Ni3Al phase and Ni5Zr intermetallic dispersoids was observed to display the microstructural feature for the present alloys investigated. Depending on alloying elements, the volume fraction of 2nd phase was measured to be different, indicating a difference in solid solubility of alloying elements in the matrix γ’ phase. Lattice parameter of matrix phase increased with increasing content of alloying elements. In the higher temperature region more than 973K, the present alloys appeared to show their higher strength compared to those obtained in conventional superalloys. On the basis of experimental results obtained, it is suggested that refractory alloying elements have an effective role to improve the high temperature strength in terms of enhanced thermal stability and solid solution hardening.


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