High temperature and room temperature tribological behaviors of in-situ carbides reinforced Ni-based composites by reactive sintering Ni and Ti2AlC precursor

Nb–silicide in situ composites have great potential for high-temperature turbine applications. Nb–silicide composites consist of a ductile Nb-based solid solution together with high-strength silicides, such as Nb5Si3and Nb3Si. With the appropriate addition of alloying elements, such as Ti, Hf, Cr, and Al, it is possible to achieve a promising balance of room-temperature fracture toughness, high-temperature creep performance, and oxidation resistance. In Nb–silicide composites generated from metal-rich binary Nb-Si alloys, Nb3Si is unstable and experiences eutectoid decomposition to Nb and Nb5Si3. At high Ti concentrations, Nb3Si is stabilized to room temperature, and the eutectoid decomposition is suppressed. However, the effect of both Ti and Hf additions in quaternary alloys has not been investigated previously. The present article describes the discovery of a low-temperature eutectoid phase transformation during which (Nb)3Si decomposes into (Nb) and (Nb)5Si3, where the (Nb)5Si3possesses the hP16 crystal structure, as opposed to the tI32 crystal structure observed in binary Nb5Si3. The Ti and Hf concentrations were adjusted over the ranges of 21 to 33 (at.%) and 7.5 to 33 (at.%) to understand the effect of bulk composition on the phases present and the eutectoid phase transformation.

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Improvement of High Temperature Wear Behavior of In-Situ Cr3C2-20 wt. % Ni Cermet by Adding Mo

Crystals ◽

10.3390/cryst10080682 ◽

2020 ◽

Vol 10 (8) ◽

pp. 682

Author(s):

Liang Sun ◽

Wenyan Zhai ◽

Hui Dong ◽

Yiran Wang ◽

Lin He

Keyword(s):

Wear Resistance ◽

High Temperature ◽

Wear Mechanism ◽

Room Temperature ◽

Wear Behavior ◽

Ceramic Particle ◽

High Temperature Wear ◽

The Coefficient Of Friction ◽

Mo Content

Cr3C2-Ni cermet is a kind of promising material especially for wear applications due to its excellent wear resistance. However, researches were mainly concentrated on the experiment condition of room temperature, besides high-temperature wear mechanism of the cermet would be utilized much potential applications and also lack of consideration. In present paper, the influence of Mo content on the high-temperature wear behavior of in-situ Cr3C2-20 wt. % Ni cermet was investigated systematically. The friction-wear experiment was carried out range from room temperature to 800 °C, while Al2O3 ceramic was set as the counterpart. According to experimental results, it is indicated that the coefficient of friction (COF) of friction pairs risen at the beginning of friction stage and then declined to constant, while the wear rate of Cr3C2-20 wt. % Ni cermet risen continuously along with temperature increased, which attributes to the converted wear mechanism generally from typical abrasive wear to severe oxidation and adhesive wear. Generally, the result of wear resistance was enhanced for 13.4% (at 400 °C) and 31.5% (at 800 °C) by adding 1 wt. % Mo. The in-situ newly formed (Cr, Mo)7C3 ceramic particle and the lubrication phase of MoO3 can effectively improve the wear resistance of Cr3C2-20 wt. % Ni cermet.

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The High-Temperature Transformation from 1T- to 3R-LixTiS2 (x = 0.7, 0.9) as Observed in situ with Neutron Powder Diffraction

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2014-0659 ◽

2015 ◽

Vol 229 (9) ◽

Cited By ~ 4

Author(s):

Dennis Wiedemann ◽

Suliman Nakhal ◽

Anatoliy Senyshyn ◽

Thomas Bredow ◽

Martin Lerch

Keyword(s):

High Temperature ◽

Powder Diffraction ◽

Electrode Material ◽

Room Temperature ◽

Lithium Ion ◽

Neutron Powder Diffraction ◽

Titanium Disulfide ◽

Temperature Transformation

AbstractLayered titanium disulfide is used as lithium-ion intercalating electrode material in batteries. The room-temperature stable trigonal 1T polymorphs of the intercalates Li

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High temperature tribological behaviors and wear mechanisms of NiAl–NbC–Ag composites formed by in-situ decomposition of AgNbO3

Tribology International ◽

10.1016/j.triboint.2019.105898 ◽

2020 ◽

Vol 141 ◽

pp. 105898 ◽

Cited By ~ 5

Author(s):

Xiaochun Feng ◽

Cheng Lu ◽

Junhong Jia ◽

Jiali Xue ◽

Qihua Wang ◽

...

Keyword(s):

High Temperature ◽

Wear Mechanisms ◽

Tribological Behaviors ◽

In Situ Decomposition

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Microstructure and microtexture of a Nb-16%Si (DS) Alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136982 ◽

1995 ◽

Vol 53 ◽

pp. 122-123

Author(s):

J. A. Sutliff ◽

B. P. Bewlay

Keyword(s):

High Temperature ◽

Directional Solidification ◽

Room Temperature ◽

Microstructural Characterization ◽

Crystallographic Analysis ◽

Directionally Solidified ◽

Heat Treated ◽

Other Orientation

In-situ composite Nb-Si alloys have been studied by several investigators as potential high temperature structural materials. The two major processing routes used to fabricate these composites are directional solidification and extrusion of arc-cast solidified ingots. In both cases a stable microstructure of primary Nb dendrites in a eutectoid of Nb and Nb5Si3 phases is developed after heat treatment. The Nb5Si3 phase is stable at room temperature and forms as a decomposition product of the high temperature Nb3Si phase. The anisotropic microstructures developed by both directional solidification and extrusion require evaluation of the texture to fully interpret the fracture and other orientation dependent mechanical behavior of these composites.In this paper we report on the microstructural characterization of a directionally solidified (DS) and heat treated Nb-16 at.%Si alloy. The microtexture of each of the phases (Nb, Nb5Si3) was determined using the Electron BackScattering Pattern (EBSP) technique for electron diffraction in the scanning electron microscope. A system employing automatic diffraction pattern recognition, crystallographic analysis, and sample or beam scanning was used to acquire the microtexture data.

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High-Temperature Tribological Performance of Hard Multilayer TiN-AlTiN/nACo-CrN/AlCrN-AlCrO-AlTiCrN Coating Deposited on WC-Co Substrate

Coatings ◽

10.3390/coatings10090909 ◽

2020 ◽

Vol 10 (9) ◽

pp. 909 ◽

Cited By ~ 1

Author(s):

Asad Alamgir ◽

Maxim Yashin ◽

Andrei Bogatov ◽

Mart Viljus ◽

Rainer Traksmaa ◽

...

Keyword(s):

High Temperature ◽

Room Temperature ◽

Energy Dispersive Spectrometry ◽

X Ray Diffraction ◽

X Ray ◽

Mechanical And Tribological Properties ◽

Diamond Indenter ◽

Scratch Tests ◽

Ball On Disc

Mechanical and tribological properties of the hard-multilayer TiN-AlTiN/nACo-CrN/AlCrN-AlCrO-AlTiCrN coating deposited on WC-Co substrate were investigated. The sliding tests were carried out using ball-on-disc tribometer at room (25 °C) and high temperatures (600 and 800 °C) with Al2O3 balls as counterpart. Nano-scratch tests were performed at room temperature with a sphero-conical diamond indenter. The surface morphology and chemical composition were investigated with scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and in-situ high-temperature X-ray diffraction (HT-XRD). The phase transition from fcc-(Al,Cr)2O3 into α-(Al,Cr)2O3 was observed at about 800 °C. The results of the tribological tests depends on the temperature, the lowest apparent and real wear volumes were observed on the coating after the test at 800 °C along with the smallest coefficient of friction (COF). The plastic deformation of the coating was confirmed in sliding and nano-scratch tests. The nano-scratch tests revealed the dependence of COF value on the temperature of the sliding tests.

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EBSD Coupled to SEM In Situ Annealing as a Tool to Identify Recrystallization Mechanisms - Application to Zr and Ta Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.486 ◽

2012 ◽

Vol 715-716 ◽

pp. 486-491

Author(s):

Nathalie Bozzolo ◽

S. Jacomet ◽

M. Houillon ◽

B. Gaudout ◽

Roland E. Logé

Keyword(s):

High Temperature ◽

Short Duration ◽

Microstructure Evolution ◽

Room Temperature ◽

Heat Treatments ◽

Cooling Rates ◽

Heating And Cooling ◽

Orientation Mapping ◽

High Heating

A heating stage as been developed to perform in-situ annealing in a SEM equipped with an EBSD system in order to study recrystallization mechanisms. High temperature treatments could then be performed inside the SEM, up to 1180°C and with high heating-and cooling-rates (~100°C.s-1). Samples were cooled down to room temperature to perform EBSD orientation mapping in between successive short-duration heat-treatments. Microstructure evolution snapshots obtained this way are presented in this paper to show recrystallization in Zircaloy4 and in pure tantalum.

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Phase transition and atomic structure of Cd6Tb 1/1 approximant to quasicrystal

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314099045 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C95-C95

Author(s):

Dan Liu ◽

Tsunetomo Yamada ◽

Cesar Gómez ◽

Vaclav Petricek ◽

Michal Dusek ◽

...

Keyword(s):

Phase Transition ◽

High Temperature ◽

Atomic Structure ◽

Room Temperature ◽

Structural Phase ◽

Icosahedral Quasicrystal ◽

Temperature Phase ◽

Temperature Structure ◽

Antiferromagnetic Ordering

We present an in-situ temperature study of the atomic structure of the 1/1 Cd6Tb approximant to an icosahedral quasicrystal. It belongs to the `Tsai' type family of quasicrystal and approximants whose archetype is the well-studied Cd-Yb system[1]. Its high temperature structure can be described as a bcc packing of a large Tsai atomic cluster, whose inner shell is a disordered tetrahedron at room temperature. As for most of the Cd6RE (RE=rare earth) approximant, the Cd6Tb phase undergoes a phase transition at 190 K to a phase of lower symmetry, resulting from an ordering of the inner tetrahedron[2]. Moreover, it has been shown that this phase undergoes a magnetic phase transition below 20 K, with an antiferromagnetic ordering of the Tb moment bearing atoms. It is thus particularly important to have a detailed structural study of this phase. We have carried out a systematic in situ measurement on a single grain from room temperature down to 40K on the crystal beam line located at the Soleil synchrotron. The structural phase transition is observed at about 190K. Using different attenuation, we have collected integrated intensity in a large dynamical range, leading to more than 60000 unique reflections in the C2/c monoclinic low temperature phase. The final wR2 values for room temperature and 40K are equal to 0.0726 and 0.0905 respectively. The resulting atomic structure will be compared to the well-studied approximant Zn6Sc, which is isostructural to Cd6Tb[3]. The ordering of the innermost tetrahedron leads to the distortion of the successive shells. The evolution of the high temperature phase, in particular just above Tc where pretransitional diffuse scattering is observed will be presented.

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Synthesis of Al2O3-Ni3Al Cermets by Room-Temperature Ball Milling of Al, Ni and Al2O3 Mixtures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.509.123 ◽

2006 ◽

Vol 509 ◽

pp. 123-128

Author(s):

Enrique Rocha-Rangel ◽

M.S. Moreno-Guerrero ◽

A. Velásquez-Naranjo ◽

Elizabeth Refugio-García

Keyword(s):

Ball Milling ◽

Room Temperature ◽

Exothermic Reaction ◽

Inert Atmosphere ◽

Reactive Sintering ◽

Sintering Process ◽

Interpenetrating Networks ◽

Heat Treated ◽

Ni3al Intermetallic

The synthesis of Al2O3-Ni3Al cermets with interpenetrating networks has been performed via a pressureless reactive sintering process. The synthesis has been induced by means of a solidstate reaction of Al + Ni + Al2O3 powders under intensive ball milling. The mixtures have been heat treated in an inert atmosphere (N2) in order to control the exothermic reaction between Ni and Al, with special care at temperatures near the melting point of Al. Dense and homogeneous microstructures have been obtained, composed by a matrix of Al2O3 reinforced with a Ni3Al intermetallic. Thermodynamic calculations indicate that such a cermet can be fabricated by in situ reaction synthesis. This suggests that a pressureless reaction sintering process may be a general route to synthesizing cermets with the prospect for the production of cermets with interpenetrating networks.

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