Phase Transformations in Equiatomic Y–Cu Powder Mixture at Mechanical Milling

Nanoscaled NiC powder is obtained by mechanical alloying of two equiatomic charges of Ni-carbon nanotubes and Ni-graphite in a high-energy planetary ball mill. Crystal structure of this carbide is a modified ZnS sphalerite type. Powder of NiC carbide is compacted by cold pressing at a pressure of 0.2 GPa, and the material obtained is used as a target for coating deposition by an electron beam technique. Thin films are deposited either on substrates from silicon wafer or fused glass. The phase composition of as-deposited coatings and after annealing at 900°C is studied. As shown, an annealing in air up to 900°С does not lead to cracking or peeling of the coatings from the substrate.

Section: Methodsmentioning

confidence: 99%

Testing of Electron Beam Technique for NiC Coating Deposition

Nakonechna¹,

Dusheiko²,

Belyavina³

et al. 2020

“…This package is elaborated using known algorithms [8] and intended for solving different XRD tasks, namely, determination of both peak positions and integral intensities of the Bragg's reflections by means of full profile analysis; carrying out qualitative and quantitative phase analysis using PDF data for phase identification and the least square method for lattice parameters refinement; testing of the structure models and refining crystal structure parameters (including coordinates, atomic position filling, texture, etc.). More details concerning of this package are presented in [9].…”

Section: Methodsmentioning

confidence: 99%

Synthesis of the WC and Mo$_2$C Carbides by Mechanical Alloying of Metal Powder and Carbon Nanotubes

Nakonechna¹,

Dashevskyi²,

Belyavina³

2018

Self Cite

Nanoscale WC and Mo 2 C carbides are synthesized from the elemental metal powder (with particle size of about 40 m; purity is not less than 99.6% wt.) and the carbon nanotubes (CNTs, with average diameter of 10-20 nm) by mechanical alloying in a high-energy planetary ball mill for the first time. Nature of interaction of the charge components at processing in a ball mill is studied on test samples (selected at each 1-2 hours of synthesis) using a complex of x-ray techniques. These techniques include: a full-profile analysis for the primary processing of diffractograms obtained with DRON-3M apparatus; qualitative and quantitative phase analysis for determining the phase composition of the products of synthesis; x-ray structural analysis to verify and refine the structural models; Williamson-Hall method for determining the grain sizes of synthesized carbides and microdistortions of their crystal lattice. Four hours of charge processing result in a formation of the hightemperature W 2 C and Mo 2 C carbides, the crystal structure of which is related to the-Fe 2 N structure type with vacancies within the metal sublattice. Further milling of W-CNT mixture (up to 10 hours) is accompanied by the W 2 C CNT WC transformation, while processing of the Mo-CNT mixture leads to its dispersion. The effect of CNTs on mechanochemical synthesis of the WC and Mo 2 C carbides is considered. As shown, the mechanical alloying of W/Mo-CNT is a highly effective method for the fabrication of the WC and Mo 2 C carbides. Due to their unique mechanical characteristics (high hardness, wear resistance, and strength), these materials are widely used in mak

“…The original software package, developed by us for the automated DRON equipment and including full complex of standard Rietveld refinement procedure, has been used for analysis and interpretation of the X-ray diffraction data obtained [12]. This package is intended for solving different XRD tasks, namely: determination of both peak positions and integral intensities of the Bragg reflections by means of full profile analysis; carrying out qualitative and quantitative phase analysis using PDF data for phase identification and the least square method for lattice parameters refinement; testing of the structure models and refining crystal structure parameters (including coordinates, atomic position filling, texture, etc.…”

Section: Methodsmentioning

confidence: 99%

“…Previously [12], we have successfully synthesized the equiatomic YCu compound after 120 min of milling a charge containing elemental yttrium and copper in a planetary ball mill in air. Here, this experiment has been carried out in argon atmosphere.…”

Section: Y-cu Nanocompositementioning

confidence: 99%

“…Equiatomic YCu compound belongs to the family of fully ordered and completely stoichiometric RM intermetallics (R-rare earth metal, M-transition metal) and is even more interesting from the point of view of its mechanical properties, namely, due to its unusual high ductility [10,11]. Although YCu intermetallic is traditionally produced by arc or induction melting, we were able to synthesize this compound in its fine-grained form by mechanical alloying route [12].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the Advanced Mechanical Properties of Fe–Cu and Y–Cu Nanocomposites Obtained by Mechanical Alloying

Dashevskyi¹,

Belyavina²,

Nakonechna³

et al. 2018

Self Cite

In this study, the Fe-Cu and Y-Cu nanocomposites are synthesized by mechanical alloying of the elemental powder mixture of the iron, copper and crushed yttrium particles in a high-energy planetary ball mill inside the argon atmosphere. Phase transformations in obtained composite materials are studied by X-ray powder-diffraction methods. The metastable supersaturated α-(Fe, Cu) solid solution is formed in the Fe-Cu nanocomposites during milling process, while the phase transformation during milling of the equiatomic Y-Cu mixture follows the reaction: Y + Cu → YCu + YCu 2. All obtained materials demonstrate improved mechanical properties. A set of measurements of the mechanical characteristics is carried out. The hardness measured for both FeCu and YCu nanocomposites is higher than that for conventional bulk alloys due to the grains' refinement during milling process. Besides, the synthesized nanocomposites are characterized by relatively low values of the Young's modulus.