TiC – Cr3C2 – WC – NiCr – Mo – C cermet plasma coatings

2021 ◽  
Vol 6 ◽  
pp. 29-39
Author(s):  
V. I. Kalita ◽  
◽  
A. A. Radiuk ◽  
D. I. Komlev ◽  
A. B. Mihai'lova ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Liquid Phase Sintering ◽  
Air Atmosphere ◽  
Local Protection ◽  
Annular Zone ◽  
The Matrix ◽  
Plasma Coatings ◽  
The Difference ◽  
Carbon Losses ◽  
Carbide Content

Two bulk cermets TiC – WC – Cr3C2 – Ni 20 % Cr – Mo – 2.8% C after liquid-phase sintering at 1400 °C for 1 hour were used to manufacture powders for plasma spraying of coatings. Cermets were obtained with limited time of mechanical alloying at the stage of mixing. Plasma coatings were sprayed on a setup with a nozzle attached to a plasmatron for local protection of the sprayed particles from the air atmosphere. The content of WC – Cr3C2 – C in the cermets provided compensation for carbon losses at all stages of coating production and the formation of an annular zone, the volume of which determines the increase in the TiC content in the coatings by 20 % and the formation of additional carbides in the matrix. The microhardness of cermet with an initial carbide content of 60% is 15.26 – 16.83 GPa with a load on the indenter of 200 G and 20.91 – 24.68 GPa with a load on the indenter of 20 G, the difference was explained by a scale factor. The contribution of the microhardness of carbides to the microhardness of cermet with an initial carbide content of 60% was estimated according to the rule of mixtures, proceeding from their volume fraction and microhardness of cermet under a load on the indenter of 20 G. In the initial powder for spraying, this contribution is high, 33.19 GPa, close to Hardness TiC. The contribution of microhardness of carbides in the coating is lower, 28.09 GPa.

Comparison of Two Approaches to Model Cure-Induced Microcracking in Three-Dimensional Woven Composites

2012 ◽  
Author(s):  
Igor Tsukrov ◽  
Michael Giovinazzo ◽  
Kateryna Vyshenska ◽  
Harun Bayraktar ◽  
Jon Goering ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Woven Composites ◽  
Finite Element Models ◽  
The Matrix ◽  
3D Woven Composites ◽  
The Difference ◽  
Resin Curing

Finite element models of 3D woven composites are developed to predict possible microcracking of the matrix during curing. A specific ply-to-ply weave architecture for carbon fiber reinforced epoxy is chosen as a benchmark case. Two approaches to defining the geometry of reinforcement are considered. One is based on the nominal description of composite, and the second involves fabric mechanics simulations. Finite element models utilizing these approaches are used to calculate the overall elastic properties of the composite, and predict residual stresses due to resin curing. It is shown that for the same volume fraction of reinforcement, the difference in the predicted overall in-plane stiffness is on the order of 10%. Numerical model utilizing the fabric mechanics simulations predicts lower level of residual stresses due to curing, as compared to nominal geometry models.

Improvement of an Ellipsoidal Void Model for Simulating Ductile Fracture Behavior

2013 ◽  
Vol 577-578 ◽  
pp. 93-96
Author(s):  
Kazutake Komori
Keyword(s):  
Finite Element ◽  
Ductile Fracture ◽  
Fracture Behavior ◽  
Fracture Strain ◽  
Volume Fraction ◽  
Deformation Gradient ◽  
Simple Relationship ◽  
The Matrix ◽  
The Difference ◽  
Deformation Gradients

An ellipsoidal void model for simulating ductile fracture behavior was proposed by the author [K. Komori: Mech. Mater., Vol. 60 (2013), p. 36]. The nominal fracture strain calculated from this model is slightly larger than that calculated from the finite-element void cell when the initial void volume fraction is specified. To decrease the difference, an assumption must be made that the deformation gradient of the void does not coincide with that of the matrix. This study proposes a simple relationship between the two deformation gradients that produces agreement between the nominal fracture strain calculated using the ellipsoidal void model and that using the finite-element void cell.

TiC plasma spray cermets

2020 ◽  
pp. 65-74
Author(s):  
V. I. Kalita ◽  
◽  
A. A. Radyuk ◽  
D. I. Komlev ◽  
A. B. Mikhailova ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Plasma Spray ◽  
Volume Fraction ◽  
Liquid Phase Sintering ◽  
Subsequent Formation ◽  
Initial Volume Fraction ◽  
The Matrix ◽  
High Microhardness ◽  
Reduction Of Oxides ◽  
Additional Hardening

The microstructure and microhardness of eleven volumetric cermets based on TiC carbide with nickel and cobalt based matrices after liquid-phase sintering at a temperature of 1400 °C were studied. It is supposed to use the research results for the subsequent formation of a powder for plasma spraying of coatings. The compositions of the matrix, additional hardening phases, and carbon were selected taking into account the specific features of the formation of plasma coatings: a decrease in the carbon content and high solidification rates of the sprayed particles with the formation of additional nanosized carbides and an increase in the volume fraction of carbides from 70 % to 88 %. As the matrix, we used the traditional composition for cermets with TiC carbide, NiCr – Mo,  and industrial powders, PGSR brands, Ni – 13.5 Cr – 2.7 Si – 4.5 Fe – 0.37 C – 1.65 B, and TAFA 1241F Co – 32 Ni – 21 Cr – 8  Al – 0.5 Y. The ring zone on TiC carbide is formed with the participation of WC, Cr3C2, TiN, matrix phases and additional carbon in the composition of cermets, 1 – 2.8 %, as a result, the initial volume fraction of TiC carbide increases 70 to 88 %. Additional carbon is consumed to reduce oxygen content at the stage of sintering (reduction of oxides). After sintering, cermets have high microhardness values at a load on an indenter of 20 G, 1940 – 3210 kgf/mm2, and lower values at a load on an indenter of 200  G, which was explained by a scale factor. The maximum calculated contribution of the hardness of the hardening phases to the hardness of the cermet was established for cermets with a Co matrix of 3681 kgf/mm2.

Deformation Behavior of Fe-Al-Co Single Crystals Containing CoAl Precipitates

2014 ◽  
Vol 783-786 ◽  
pp. 2869-2874 ◽  
Author(s):  
Hiroyuki Y. Yasuda ◽  
Kentaro Soma ◽  
Yoshiaki Odawara
Keyword(s):  
Single Crystals ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
High Strength ◽  
Misfit Strain ◽  
High Yield ◽  
The Matrix ◽  
Primary Slip System ◽  
The Difference ◽  
B2 Structure

The effect of the CoAl precipitates on the deformation behavior of Fe-15.0Al-15.0Co (at.%) single crystals was examined. The spherical CoAl phase with the B2 structure was precipitated in the single crystals and was stable below 974 K. The bcc matrix and CoAl phase satisfied the cube-on-cube orientation relationship with a misfit strain of 0.25%. The single crystals showed a high yield stress up to 923 K while the stress dropped at 1023 K due to the dissolution of the CoAl phase into the matrix. Moreover, the activated sip system of the crystals containing the CoAl precipitates depended strongly on loading axis. At <149> orientation, {101} <111> slip favorable for the bcc matrix and the CoAl precipitates were sheared by a pair of 1/2<111> dislocations without forming Orowan loops. The CoAl single phase was known to hardly deform by <111> slip which resulted in high strength at <149> orientation. In contrast, {010} <001> or {hk0} <001> slip favorable for the CoAl precipitates was activated at <011> orientation, although the volume fraction of the CoAl phase was very small. <001> slip was generally impossible to take place in the bcc matrix, leading to the extreme hardening. Therefore, the difference in primary slip system between the bcc matrix and CoAl precipitates was responsible for the significant precipitation hardening.

ANALISIS SIFAT MEKANIK KOMPOSIT LAMINA BERPENGUAT SERAT KACA WOVEN DENGAN MATRIKS UNSATURATED POLYESTER 2504 APT

ROTOR ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Naafi' Ul Amri ◽  
Gaguk Jatisukamto ◽  
Sumarji Sumarji
Keyword(s):  
Flexural Strength ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Fiber Volume ◽  
Axis Direction ◽  
Matrix Volume ◽  
The Matrix ◽  
The Difference

Polymer composites has anisotropic properties, if it receives stress from outside it will increase deformation in all directions. This study aims to determine the effect of composites lamina made from woven glass fibers on 2504 APT unsaturated polyester on tensile and flexural strength. The research methodology used is as follows: the process of making composites using the Hand-Lay Up method, the matrix volume fraction Vfm = 69, 39%, the fiber volume fraction Vfs = 30, 38%. The research parameters observed are the x-direction stress (sx) and the y-axis direction strees, (sy). The results obtained are the y-axis, (sy) = 0.8% greater than the x-axis. The flexural strength of the x-axis direction, (sbx) = 57,7% greater than the y-axis direction. The difference in the value of the tensile strength occurs in the number of different fiber bonds, while the flexural strength of the y direction occurs in the fiber lamina which increases more.

Formation of Persistent Slip Band in Fatigued Copper Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 470-471
Author(s):  
N. Y. Jin
Keyword(s):  
Volume Fraction ◽  
Fatigue Cracks ◽  
Wall Structure ◽  
Matrix Structure ◽  
Dislocation Dipole ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
The Matrix ◽  
Hard Shell ◽  
Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

Development of Prolonged Delivery of Tramadol and Dissolution Translation by Statistical Data Treatment

2011 ◽  
Vol 4 (1) ◽  
pp. 1331-1337
Author(s):  
P B Parejiya ◽  
B S Barot ◽  
P K Shelat
Keyword(s):  
Drug Release ◽  
Study Data ◽  
Stability Study ◽  
Dissolution Time ◽  
Matrix Tablet ◽  
Burst Effect ◽  
The Matrix ◽  
The Mean ◽  
The Difference ◽  
Dissolution Efficiency

The present study was carried out to fabricate a prolonged design for tramadol using Kollidon SR (Polyvinyl acetate and povidone based matrix retarding polymer). Matrix tablet formulations were prepared by direct compression of Kollidon SR of a varying proportion with a fixed percentage of tramadol. Tablets containing a 1:0.5 (Drug: Kollidon SR) ratio exhibited a rapid rate of drug release with an initial burst effect. Incorporation of more Kollidon SR in the matrix tablet extended the release of drug with subsequent minimization of the burst effect as confirmed by the mean dissolution time, dissolution efficiency and f2 value. Among the formulation batches, a direct relationship was obtained between release rate and the percentage of Kollidon SR used. The formulation showed close resemblance to the commercial product Contramal and compliance with USP specification. The results were explored and explained by the difference of micromeritic characteristics of the polymers and blend of drug with excipients. Insignificant effects of various factors, e.g. pH of dissolution media, ionic strength, speed of paddle were found on the drug release from Kollidon-SR matrix. The formulation followed the Higuchi kinetic model of drug release. Stability study data indicated stable character of Batch T6 after short-term stability study.

Study of pumping effect in flow-through electrolysers

1983 ◽  
Vol 48 (8) ◽  
pp. 2232-2248 ◽  
Author(s):  
Ivo Roušar ◽  
Michal Provazník ◽  
Pavel Stuhl
Keyword(s):  
Natural Convection ◽  
Balance Equation ◽  
Volume Fraction ◽  
Industrial Applications ◽  
Pumping Effect ◽  
Flow Through ◽  
The Mean ◽  
The Difference

In electrolysers with recirculation, where a gas is evolved, the pumping of electrolyte from a lower to a higher level can be effected by natural convection due to the difference between the densities of the inlet electrolyte and the gaseous emulsion at the outlet. An accurate balance equation for calculation of the rate of flow of the pumped liquid is derived. An equation for the calculation of the mean volume fraction of bubbles in the space between the electrodes is proposed and verified experimentally on a pilot electrolyser. Two examples of industrial applications are presented.

Sign in / Sign up

Export Citation Format

Share Document