scholarly journals Microstructure and mechanical properties of HR6W alloy dedicated for manufacturing of pressure elements in supercritical and ultrasupercritical power units

2019 ◽  
Vol 82 ◽  
pp. 01005 ◽  
Author(s):  
Grzegorz Golański ◽  
Agata Merda ◽  
Adam Zieliński ◽  
Paweł Urbańczyk ◽  
Jacek Słania ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Base Alloy ◽  
Strength Properties ◽  
Laves Phase ◽  
Plastic Properties ◽  
The Matrix ◽  
Isothermal Ageing ◽  
Nickel Base

The article presents the results of research on the microstructure and selected mechanical properties of HR6W nickel-base alloy. The test alloy was subjected to isothermal ageing at 700°C and for up to 10000h. The tests of the HR6W microstructure were performed using the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The performed microstructural tests of the HR6W alloy showed that in the as-received condition it was characterised by the structure of nickel austenite with numerous primary precipitates of NbC and TiN. Ageing of the investigated alloy contributed to the precipitation of numerous particles of varying morphologies inside the grains and at the grain boundaries, as well as at the boundaries of twins - they were the secondary precipitates of M23C6 and Laves phase. The number of the particles precipitated at the boundaries was so large that they formed the so-called continuous grid of precipitates. Inside the grains, the presence of compound complexes of precipitates was observed. These complexes consisted of the TiN particles, as well as the M23C6 carbides and Laves phase nucleating on them. The tests of the mechanical properties of HR6W alloy showed that in the as-received condition the alloy showed high plastic properties, with relatively low strength properties - in particular, the yield strength. Ageing of the HR6W alloy, as a result of precipitation of numerous particles in the matrix, through the strengthening with the precipitation mechanism, resulted in a considerable growth of the strength properties - inter alia the yield strength by over 60%, with the reduction of the plastic properties - elongation decreased by around 40%. Similar growth in the test alloy was observed for hardness.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

scholarly journals Microstructure Characteristics and Strengthening Behavior of Cu-Bearing Non-Oriented Silicon Steel: Conventional Process versus Strip Casting

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1815
Author(s):  
Feng Fang ◽  
Diwen Hou ◽  
Zhilei Wang ◽  
Shangfeng Che ◽  
Yuanxiang Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
High Speed ◽  
Silicon Steel ◽  
Strip Casting ◽  
Precipitation Strengthening ◽  
Conventional Process ◽  
Core Losses ◽  
The Matrix ◽  
Bcc Structure

Based on conventional hot rolling processes and strip casting processes, Cu precipitation strengthening is used to improve the strength of non-oriented silicon steel in order to meet the requirements of high-speed driving motors of electric vehicles. Microstructure evolution was studied, and the effects of Cu precipitates on magnetic and mechanical properties are discussed. Compared with conventional processes, non-oriented silicon steel prepared by strip casting exhibited advantages with regard to microstructure optimization with coarse grain and {100} texture. Two-stage rolling processes were more beneficial for uniform microstructure, coarse grains and improved texture. The high magnetic induction B50 of 1.762 T and low core losses with P1.5/50, P1.0/400 and P1.0/1000 of 1.93, 11.63 and 44.87 W/kg, respectively, were obtained in 0.20 mm sheets in strip casting. Cu precipitates significantly improved yield strength over ~120 MPa without deteriorating magnetic properties both in conventional process and strip casting. In the peak stage aged at 550 °C for 120 min, Cu precipitates retained bcc structure and were coherent with the matrix, and the yield strength of the 0.20 mm sheet was as high as 501 MPa in strip casting. The main mechanism of precipitation strengthening was attributed to coherency strengthening and modulus strengthening. The results indicated that balanced magnetic and mechanical properties can be achieved in thin-gauge non-oriented silicon steel with Cu addition in strip casting.

The Impact Properties of a Polyurethane Composite Filled with Clay

2011 ◽  
Vol 197-198 ◽  
pp. 1100-1103
Author(s):  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Mechanical Analysis ◽  
Impact Testing ◽  
Impact Properties ◽  
Polyurethane Composite ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

A polyurethane/clay (PU/clay) composite was synthesized. The microstructure of the composite was examined by scanning electron microscopy. The impact properties of the composite were characterized by impact testing. The study on the structure of the composite showed that clays could be dispersed in the polymer matrix well apart from a few of clusters. The results from mechanical analysis indicated that the impact properties of the composite were increased greatly in comparison with pure polyurethane. The investigation on the mechanical properties showed that the impact strength could be obviously increased by adding 20 wt% (by weight) clay to the matrix.

A Study of Phase Reactions in a Complex 4.5 Al–3.5 Ti–Ni Base Alloy

1960 ◽  
Vol 4 ◽  
pp. 233-243
Author(s):  
John F. Radavich ◽  
W. J. Boesch
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Structural Changes ◽  
Base Alloy ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
High Temperature Alloy ◽  
X Ray ◽  
Nickel Base ◽  
Precipitated Phases

AbstractAn investigation of the phase changes in a complex aluminum-titanium-hardened nickel-base high-temperature alloy was carried out after solutioning at high temperatures and aging at lower temperatures. The physical distribution and size of the precipitated phases were studied by electron microscopy. X-ray diffraction and fluorescence analyses were carried out on chemically extracted residues. The results of the xtructure changes as well as correlation of some physical properties with the structural changes are presented.

Regulation of Mechanical Properties of Advanced PCM Products with the Aid of Catalysts

2020 ◽  
Vol 992 ◽  
pp. 415-420
Author(s):  
I.V. Zaychenko ◽  
V.V. Bazheryanu ◽  
A.G. Kim
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Temperature Gradient ◽  
Polymer Composite ◽  
Strength Properties ◽  
Polymer Composite Materials ◽  
Epoxy Binder ◽  
Curing Process ◽  
The Matrix

The article considers the problem of the effect of uneven curing caused by the temperature gradient across the thickness of the material on the anisotropy of the strength properties of polymer composite materials. The effect of catalysts on the curing of the epoxy binder EDT-69N, used for the manufacture of multilayer polymer composite materials, was studied. According to dielectric spectrometry, the accelerating effect of the selected compounds on the curing process of the EDT-69N epoxy binder during fiberglass molding has been proved. The possibility of controlling the curing process using catalysts to reduce the influence of the temperature gradient on the anisotropy of the strength properties of the matrix in the manufacture of polymer composite materials is shown.

scholarly journals TEM observation of precipitates and their role to mechanical properties in Ti-5553 alloy heated to some temperatures up to 923 K

2020 ◽  
Vol 321 ◽  
pp. 11035
Author(s):  
E. Sukedai ◽  
E. Aeby-Gautier ◽  
M. Dehmas
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Hardening Mechanism ◽  
Transmission Electron ◽  
The Matrix ◽  
Higher Temperature ◽  
Shearing Mechanism ◽  
Hardness Values ◽  
Measured Hardness

A Ti-5553 specimen was continuously heated to 923 K and simultaneously in-situ HEXRD profiles were taken. In addition, specimens heated at the same rate to several temperatures up to 923 K and further quenched were observed by transmission electron microscopy. Based on both results obtained, transformation sequence was clarified, precipitations of ω-, α”iso- and α-phases were confirmed, and size and density of these precipitates were measured. Hardness values of those specimens were also measured. The hardening mechanism was considered as shearing-mechanism for specimens aged at lower temperatures and by-pass one for specimens aged at higher temperature. An attempt of distinction between α”iso - and α-precipitates was also tried. Both precipitates were in needle-like shape and a possibility was suggested by measuring angles between two needle-shape precipitates on {110} of the matrix and comparing with each other.

Effect of Al and Ti Additions in Cast Nickel Base Alloy, Grade Hastelloy X by Arc Melting Process on Microstructures and Oxidation Behavior at 900°C and 1000°C

2014 ◽  
Vol 548-549 ◽  
pp. 274-279 ◽  
Author(s):  
Pajaree Srigiofun ◽  
Panyawat Wangyao ◽  
Gobboon Lothongkum ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Oxidation Resistance ◽  
Base Alloy ◽  
Melting Process ◽  
Vacuum Arc ◽  
Nickel Base Alloy ◽  
Hastelloy X ◽  
Σ Phase ◽  
Arc Melting ◽  
The Matrix ◽  
Nickel Base

The nickel base alloy, grade Hastelloy X was modified by Aluminum and Titanium additions by means of vacuum arc melting process in order to improve microstructural characteristics and oxidation resistance. The arc melted Hastelloy X was added Aluminum and Titanium each for 2%, 4% and 6% by weight. Then all specimens were performed with heat treatment, which consists of solutioning treatment at 1125°C for 24 hours and precipitation aging at temperatures of 760°C, 800°C and 845°C for 24 hours. Both aluminum and titanium additions resulted in network intermetalic phase formation, namely, σ-phase, throughout the matrix. Furthermore, the addition of both elements provided the better oxidation resistance for the alloys.

scholarly journals Effect of Two-Stage Homogenization Heat Treatment on Microstructure and Mechanical Properties of AA2060 Alloy

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Chaoyang Chaoyang ◽  
Guangjie Guangjie ◽  
Lingfei Lingfei ◽  
Fei Fei ◽  
Lin Lin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cast Alloy ◽  
Hardness Test ◽  
Test Methods ◽  
Al Alloy ◽  
Two Stage ◽  
Homogenization Treatment ◽  
Transmission Electron ◽  
The Matrix

The microstructure evolution of AA2060 Al alloy containing Li during two-stage homogenization treatment was investigated by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), mechanical properties and Vickers micro-hardness test methods. The results demonstrate that severe precipitation of θ(Al2Cu) and S(Al2CuMg) phase existed in the as-cast alloy, especially in the center position. Cu elements were concentrated at grain boundary and gradually decreased from the boundary to the interior. Numerous eutectic phases of θ(Al2Cu) and S (Al2CuMg) containing Zn and Ag elements were segregated at grain boundaries. The overheating temperature of the as-cast alloy is 497 °C. After two-stage homogenization treatment, the θ(Al2Cu) and S (Al2CuMg) in the surface, middle and center positions were completely dissolved into the matrix, thus achieved uniform homogenization effect. Moreover, water cooling could prevent the precipitation after homogenization, which provided good performance of the studied alloy. The optimum two-stage homogenization treatment of AA2060 alloy was 460 °C/4 h + 490 °C/2 4 h. The homogenization kinetic analysis was discussed as well.

scholarly journals Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Basal Spacing ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Thermal Stability Of

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

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