Influence of Hot Forging on the Elastic Properties and Character of Anisotropy of Powder Composites with Titanium Matrix

In the present work, titanium matrix composites reinforced with TiB, TiC, and Re2O3 (Nd2O3 or Y2O3) were fabricated via common casting and hot-forging technology utilizing the chemical reaction between Ti, B4C (or C), rare earth (Re) and B2O3 through homogeneously melting in a non-consumable vacuum arc remelting furnace. In this work, Nd and Y were chosen as rare earth (Re) added in the in situ reaction. The thermodynamics of in situ synthesis reactions was studied. The results of X-ray diffraction (XRD) proved that no other phases appeared except for TiB, TiC and Re2O3. The microstructures of the composites were examined by optical microscopy (OM). The results showed that there were mainly three kinds of reinforcements: TiB whiskers, TiC particles and Re2O3 particles. The reinforcements were fine and were homogeneously distributed in the matrix. The interfaces of TiB-Ti and Y2O3-Ti have been examined by high-resolution transmission electron microscopy (HREM).Transmission electron microscopy (TEM) and selected area diffraction (SAD) were used to analyze the orientation relationships of TiB-Ti, Nd2O3-Ti, and Y2O3-Ti. The mechanical properties at room temperature improved with the addition of TiB whiskers and TiC particles although some reduction in ductility was observed. The (TiB+TiC)/Ti6242 composite with TiB:TiC=1:1 shows higher tensile strength and ductility.

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Development of composite powders and coatings for protection and restoration of products under significant temperature exposure during operation

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2020-103-3-70-78 ◽

2020 ◽

pp. 70-78

Author(s):

T. I. Bobkova ◽

A. A. Grigoriev ◽

D. S. Zhirov

Keyword(s):

Experimental Data ◽

Thermal Spraying ◽

Engineering Industry ◽

Titanium Matrix ◽

Composite Powders ◽

Powder Composites ◽

Significant Temperature ◽

Temperature Exposure ◽

Sprayed Coatings ◽

Nanostructured Powders

The paper presents results of studies aimed at expanding the range of domestic powder composites for thermal spraying of coatings with great number of performance characteristics used in the power engineering industry. Experimental data on the synthesis of nanostructured powders based on a titanium matrix and reinforced with ceramic nanopowders are presented. Some properties of sprayed coatings are investigated.

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Grain Refinement in Titanium-Erbium Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052626 ◽

1974 ◽

Vol 32 ◽

pp. 522-523

Author(s):

B. B. Rath ◽

J. E. O'Neal ◽

R. J. Lederich

Keyword(s):

Electron Microscopy ◽

Size Distribution ◽

Grain Refinement ◽

Grain Growth ◽

Volume Fraction ◽

Pure Titanium ◽

Systematic Investigation ◽

Second Phase ◽

Titanium Matrix ◽

Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

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Electron Microscopy and image reconstruction reveal the structural basis for spectrin's elastic properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122952 ◽

1992 ◽

Vol 50 (1) ◽

pp. 510-511

Author(s):

Amy M. McGough ◽

Robert Josephs

Keyword(s):

Electron Microscopy ◽

Elastic Properties ◽

Conformational Changes ◽

Quaternary Structure ◽

Three Dimensional ◽

Membrane Skeleton ◽

Projection Algorithm ◽

Structural Basis ◽

Iterative Approximation ◽

Membrane Skeletons

The remarkable deformability of the erythrocyte derives in large part from the elastic properties of spectrin, the major component of the membrane skeleton. It is generally accepted that spectrin's elasticity arises from marked conformational changes which include variations in its overall length (1). In this work the structure of spectrin in partially expanded membrane skeletons was studied by electron microscopy to determine the molecular basis for spectrin's elastic properties. Spectrin molecules were analysed with respect to three features: length, conformation, and quaternary structure. The results of these studies lead to a model of how spectrin mediates the elastic deformation of the erythrocyte.Membrane skeletons were isolated from erythrocyte membrane ghosts, negatively stained, and examined by transmission electron microscopy (2). Particle lengths and end-to-end distances were measured from enlarged prints using the computer program MACMEASURE. Spectrin conformation (straightness) was assessed by calculating the particles’ correlation length by iterative approximation (3). Digitised spectrin images were correlation averaged or Fourier filtered to improve their signal-to-noise ratios. Three-dimensional reconstructions were performed using a suite of programs which were based on the filtered back-projection algorithm and executed on a cluster of Microvax 3200 workstations (4).

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The buckling of thin EM specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177386 ◽

1990 ◽

Vol 48 (4) ◽

pp. 850-851

Author(s):

A.R. Thölén

Keyword(s):

Electron Microscope ◽

Elastic Properties ◽

Crystal Surface ◽

Specimen Surface ◽

Radius Of Curvature ◽

Thin Foils ◽

Thin Electron ◽

Regular Patterns

Thin electron microscope specimens often contain irregular bend contours (Figs. 1-3). Very regular bend patterns have, however, been observed around holes in some ion-milled specimens. The purpose of this investigation is twofold. Firstly, to find the geometry of bent specimens and the elastic properties of extremely thin foils and secondly, to obtain more information about the background to the observed regular patterns.The specimen surface is described by z = f(x,y,p), where p is a parameter, eg. the radius of curvature of a sphere. The beam is entering along the z—direction, which coincides with the foil normal, FN, of the undisturbed crystal surface (z = 0). We have here used FN = [001]. Furthermore some low indexed reflections are chosen around the pole FN and in our fcc crystal the following g-vectors are selected:

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