Vibratory Ball Research Articles

Composite Materials Based on EN AW-Al Cu4Mg1(A) Aluminum Alloy Reinforced with the Ti(C,N) Ceramic Particles

Investigations of composite materials based on EN AW-Al Cu4Mg1(A) aluminum alloy reinforced with the Ti(C,N) particles with various weight ratios of 5, 10, and 15% are presented. Powders of the starting materials were mixed in the laboratory vibratory ball mill to acquire the uniform distribution of reinforcement particles in the matrix material. The components were initially compacted at cold state in a die with the diameter of ∅ 26 mm in the laboratory vertical unidirectional press – with a capacity of 350 kN. The obtained P/M compacts were heated to a temperature of 480÷500°C and finally extruded – with the extrusion pressure of 500 kN. Bars with a diameter of 8 mm were obtained as the end product. Based on the microstructural examinations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminum matrix was revealed. Hardness tests, tensile tests and the ultimate compressive strength tests made it possible demonstrate that all these properties change along with the reinforcing particles concentration change.

Study on Grinding Waviness on Outer Race of Ball Bearing and Vibration Reducing Skills

Visible waviness on the ball bearing’s outer ring groove, which processed by groove grinder, results in a lower precision of post processing. To reduce the waviness, some experiments are conducted to analyze the property of grinder structure. Accord to analysis result, a modification scheme is provided. In scheme an equilibrant device is designed on the grinding wheel shaft, and rotation of grinding wheel shaft with equilibrant device is simulated with the MSC.visualNastran software.

Synthesis of titanium aluminide coatings on aluminum and titanium surfaces by mechanical alloying and subsequent annealing

Intermetallic Ti-Al-based coatings were synthesized by mechanical alloying in a vibratory ball mill and subsequent annealing. A titanium layer was deposited on aluminum specimens and an aluminum layer and aluminum-titanium mixture were deposited on titanium specimens. Under the effect of milling balls, powder particles deposit at the substrates, forming layers that have a very good cohesion with the substrate. During subsequent heating, diffusion layers on the basis of titanium-aluminum phases are synthesized as a result of the chemical interaction between titanium and aluminum. In the case of titanium layer deposited on aluminum, the temperature interval of transformations is 600–650°C; first, a Ti3Al5-based phase is formed; then, as diffusion saturation with Al increases, an Al2Ti-based layer appears; and finally, the Al3Ti compound is formed. The reaction rates depend on the temperature and the duration of annealing. On titanium with a (Ti + Al) layer deposited on its surface, the Al3Ti, Al2Ti, TiAl, and Ti3Al compounds are formed in a temperature interval of 600–900°C. In the case of deposition a homogeneous aluminum layer on titanium, only Al3Ti and Ti3Al phases were observed after annealing.

The structure and properties of PM composite materials based on EN AW-2124 aluminum alloy reinforced with the BN or Al 2O 3 ceramic particles

Investigations of composite materials based on EN AW-2124 aluminum alloy reinforced with the BN or Al 2O 3 particles with various weight ratios of 5, 10 and 15% are presented. Powders of the starting materials were mixed in the laboratory vibratory ball mill to acquire the uniform distribution of reinforcement particles in the matrix material. The components were initially compacted at cold state in a die with the diameter of Ø 26 mm in the laboratory vertical unidirectional press—with a capacity of 350 kN. The obtained P/M compacts were heated to a temperature of 480/500 °C and finally extruded—with the extrusion pressure of 500 kN. Bars with a diameter of 8 mm were obtained as the end product. Based on the microstructural examinations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminum matrix was revealed. Hardness tests, static tensile tests and the compressive tests made it possible to demonstrate that all these properties change along with the reinforcing particles concentration change. As an example, hardness increased from 89 HV1 for the material without the reinforcing phase to 123 HV1 for 15% of BN, and the ultimate compressive strength decreases along with the increase of the reinforcing phase fraction from 667 MPa for 5% to 472 MPa for 15% of BN.

Effect of MnS powder additions and vibratory ball peening on corrosion resistance of sintered 316LSC stainless steels

As sintered parts are to be machined after sintering, the MnS powder is usually added to improve the machinability. Vibratory ball peening is used for deburring and improving the surface finish of sintered components in local PM industries. The effect of the MnS powder content and vibratory ball peening on the corrosion resistance of the sintered 316LSC alloys was investigated. Experimental results show that the addition of MnS powder slightly decreases the sintered density. The weight loss rate of the sintered specimens immersed in the 10%FeCl3 corrosion test solution increases slightly with increas- ing MnS content, but decreases with increasing sintering temperature. Vibratory ball peening effec- tively decreases the weight loss rate of the sintered stainless steels. The chromium atoms actively migrate across the phase boundary and diffuse into the MnS particles during sintering. This intensive chromium diffusion affects the corrosion performance of the sintered alloys with MnS added. The surface morphology of the as sintered and the ball peened specimens before and after the corrosion test were studied with a SEM.

Structure, properties and corrosion resistance of PM composite materials based on EN AW-2124 aluminum alloy reinforced with the Al 2O 3 ceramic particles

Investigations of composite materials based on EN AW-2124 aluminum alloy reinforced with the Al 2O 3 particles with various weight ratios of 5, 10, and 15% are presented. Powders of the starting materials were mixed in the laboratory vibratory ball mill to acquire the uniform distribution of reinforcement particles in the matrix material. The components were initially compacted at cold state in a die with the diameter of ∅26 mm in the laboratory vertical unidirectional press with a capacity of 350 kN. The obtained P/M compacts were heated to a temperature of 480–500 °C and finally extruded with the extrusion pressure of 500 kN. Bars with a diameter of 8 mm were obtained as the end product. Based on the microstructural examinations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminum matrix was revealed. Hardness tests and the ultimate compressive strength tests made it possible demonstrate that both these properties change along with the reinforcing particles concentration change. As an example, hardness increased from 89.27 HV1 for the material without the reinforcing phase to 123.4 HV1 for 15% Al 2O 3, and the ultimate compressive strength decreases along with the increase of the reinforcing phase fraction from 798 MPa for 5% to 663 MPa for 15% Al 2O 3. Results of the corrosion tests, determined using the potentiodynamic method in the 3% water solution of NaCl indicate that corrosion of the investigated composite materials depends on the volume fraction of the reinforcing particles. It was found out, based on the determined anode polarisation curves that the investigated materials are susceptible to pitting corrosion. Moreover, investigation results indicate that the composite materials reinforced with the ceramic particles with the portions of 5 and 10% are characteristic of a higher corrosion resistance in the selected environment, compared to the matrix material, whereas at the 15% portion this resistance it worse, the anode digestion current grows.

Fabrication of ultrafine W – Cu powders by mechanical alloying

Ultrafine composite powders of W – 15 wt-%Cu, W – 25 wt-%Cu, and W – 35 wt-%Cu have been fabricated by mechanical alloying. The effects of type of mill, process control agent, temperature of milling, and ball/powder ratio on the final products have been evaluated. The results show that the planetary ball mill possesses a higher impact energy intensity than that of the vibratory ball mill. The optimum milling time is confirmed by the formation of a nanocrystalline microstructure in the planetary ball mill after optimisation of the milling parameters. A steady state between cold welding and fracture is attained with a milling time of up to 25 h in the planetary ball mill under optimised conditions. Crystallites with sizes of 7 – 8 nm for W – Cu composite powders have been obtained after 25 h of ball milling. The powders obtained after mechanical alloying have been characterised in terms of their size, shape, phase constitution, and microstructural features using X-ray diffraction and scanning electron microscopy.

Kinetic analysis of the mechanolysis of polymethylmethacrylate in the course of vibratory ball milling at various mechanical energy

AbstractWe carried out the mechanolysis of polymethylmethacrylate (PMMA) at various mechanical energies and analyzed kinetically the mechanoradical concentration and molecular weight at various mechanical energies. The radical concentration gradually increased to a maximum and then gradually decreased after reaching the maximum value. It is suggested that the radical quenching reaction (disproportionation and/or recombination) progressed together with radical formation. Kinetic analysis of the mechanoradical concentration indicated that the actual amounts of mechanoradicals produced were larger than observed. It is also suggested that vast numbers of reactions take place in mechanolysis. The molecular weight decreased exponentially toward the limiting value, and the limiting molecular weight was larger with decreases in mechanical energy. It is also suggested that mechanoradical formation is inversely proportional to the change in molecular weight at any given mechanical energy. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4161–4167, 2004

Effects of short-time vibratory ball milling on the shape of FT-IR spectra of wood and cellulose

Vibratory ball milling is shown to have a strong influence on the shape of FT-IR spectra of wood and cellulose, even if the samples are milled for only a short time. The results show that neither temperature nor particle size or oxidation processes are the most important reason for the observed changes in the structure of the FT-IR spectra, but that the mechanical treatment itself is the main influencing factor. Studies of the effects of temperature, particle size, oxygen and mechanical treatment on chemical and structural changes are presented. The most conspicuous changes in the spectra of cellulose and wood were observed at wave numbers 1034, 1059, 1110, 1162, 1318, 1335, 2902 cm −1 and in the OH-stretching vibration region from 3200 to 3500 cm −1. It is suggested that these changes are mainly associated with a decrease in the degree of crystallinity and/or a decrease in the degree of polymerisation of the cellulose.

Effects of reactive mechanical milling conditions on the physico-chemical properties of Mg+Cr 2O 3 mixtures

The influence of the mechanical grinding (MG) (under reactive atmosphere of hydrogen) conditions on the physico-chemical properties (crystallography, phase composition, morphology and hydrogen sorption properties) of a Mg+5% Wt.% Cr 2O 3 mixture are examined. Both a planetary and a vibratory ball miller have been used. In the case of the planetary ball miller, different rotation speeds (200, 250 and 300 rpm), and ball to powder mass ratios were investigated. It appears that the planetary ball miller allows to obtain finer particles and also more amorphous materials. The relationship between crystallinity, morphology and injected power was established.

Riboflavin-radical formation by mechanochemical solid-state reaction using stainless steel vessel

The mechanochemical reaction of free riboflavin (FR) due to vibratory ball milling was carried out in a stainless steel vessel at room temperature under anaerobic conditions. The ESR of the fractured sample showed a broad single-line spectrum. It is suggested that the solid-state single-electron transfer (SSET) reaction from the surface of the stainless steel vessel to FR proceeded during the vibratory milling, resulting in the formation of the corresponding anion radicals. When the mechanochemical reaction of FR in the presence of calcium pantothenate (PC) was carried out, the radical concentration increased with the increasing PC content. It was shown that the anion radical in the metal complex was stable for a lengthy period of time even in highly humid air.

Evaluation of Ti3SiC2 Prepared by Mechanical Alloying

The synthesis of Ti3SiC2 powder by mechanical alloying (MA) from elemental Ti, Si and C powders and evaluation of some properties of the sintered compacts of the MA powder were conducted. MA was carried out by vibratory ball milling and planetary ball milling. The influence of parameters, such as running time, ball size and rotation speed on MA powder were examined. The annealing of the MA powder was done at various temperatures and holding times. The MA powders could be sintered to dense Ti3SiC2-based ceramics which contained TiC as a secondary phase. Mechanical, thermal and electrical properties of sintered compacts were evaluated. The Ti3SiC2-based compact showed low hardness, high Young's modulus, and plastic behavior at high temperatures over 1373 K, And the compact showed high thermal expansion, high thermal conductivity, and higher electrical conductivity than other conventional ceramics.

Preparation of A Thermoelectric Composite of AgSbTe2/Ag2Te by Mechanical Alloying

Synthesis of AgSbTe2/Ag2Te composite by mechanical alloying from elemental powders is described. Mechanical alloying was done by vibratory ball milling with a ball-to-powder ratio of 100:1. The studied composition range was Sb2Te3-xmol%Ag2Te (x=43-70); the (β+Ag2Te) region in the Sb2Te3-Ag2Te phase diagram. XRD analysis showed that after sufficient milling β compound AgSbTe2 was found to be formed for x=43. The composites of various compositions were formed depending on the initial mixing ratios. The sintered compacts of the mechanically alloyed powders had homogeneous composite microstructures and exhibited the increase in the connectivity of the second phase Ag2Te in the AgSbTe2 matrix with increase in the Ag2Te content.

Rietveld analysis of polymorphic transformations of ball milled anatase TiO 2

Rietveld’s whole powder profile fitting method based on crystal structure refinement is applied to extract the microstructure information of several polymorphic TiO 2 phases grown simultaneously during high energy vibratory ball milling of anatase phase. Warren–Averbach’s method of X-ray line profile analysis is also made for comparison of above results. The X-ray powder patterns of four TiO 2 phases along with α-Al 2O 3 (contamination) are simulated simultaneously for the first time to fit the experimental X-ray powder patterns of multiphase materials. The structural details of monoclinic TiO 2 (B) phase are also reported first time in this paper. The advantages of the present method of analysis over the other methods of X-ray line profile analysis are discussed in details.

Actual behaviour of a ball vibration absorber

This paper describes the theory, experiments and practical application of the ball vibration absorber for horizontal movement, as well as its efficiency in comparison with that of the pendulum absorber. Two prototypes of such absorbers were recently installed on small TV towers in the Czech Republic and their dynamic behaviour examined. The laboratory test of an absorber of actual dimensions confirmed its efficiency.

Mössbauer study of ball-milled Fe-Ge alloys

In this work the mechanical alloying of ${\mathrm{Fe}}_{100\ensuremath{-}x}{\mathrm{Ge}}_{x}$ was studied as a function of alloying composition $(9<~x<~40)$ processing time and annealing treatment. The alloys were prepared using a high-energy vibratory ball mill. For $9<~x<~27.5$ a single phase $A2$ solid solution was formed while for $x>~30$ besides the solid solution an increasing amount of disordered ${B8}_{1}$ (NiAs type) ${\mathrm{Fe}}_{3}{\mathrm{Ge}}_{2}$ was found. Thermally induced $A\stackrel{\ensuremath{\rightarrow}}{2}{D0}_{3}$ transition was investigated for $9<~x<~27.5.$ The detailed annealing temperature dependence of short- and long-range ordering into the ${D0}_{3}$ structure was studied for the case of ${\mathrm{Fe}}_{75}{\mathrm{Ge}}_{25}$ by means of M\"ossbauer-effect spectroscopy and x-ray diffraction. The solid solution orders gradually and homogenously into the ${D0}_{3}$ structure. To follow and quantify the evolution of short-range order a special fitting routine for M\"ossbauer spectra was used that takes into account local and nonlocal contributions to the hyperfine interactions experienced by a ${}^{57}\mathrm{Fe}$ probe, and that assumes nonlinearity dependences on the number of neighbors of a given class. By this means the short-range ${D0}_{3}$ order parameter S was determined for as milled steady states as well as annealed states for $9<~x<~27.5.$ In the case of ${\mathrm{Fe}}_{75}{\mathrm{Ge}}_{25}$ the evolution of mechanical alloying with time was investigated. It was found that alloying proceeds in two stages. In the first one, iron rich (with $A2$ structure) and disordered Ge-rich regions coexist along with an almost equiatomic $A2$ Fe-Ge solid solution, which was interpreted as an interphase physically located between the former two. The three phases collapse into just one bcc solid solution with $S\ensuremath{\approx}0.3$ for a critical time ${t}_{c},$ which was identified as the chemical mixing time reported by other authors. The second stage of mechanical alloying produces the complete homogenization of the solid solution. Plausible basic mechanisms of mechanical alloying of Fe-Ge mixtures are discussed on the basis of the results presented here.

Effect of ball-charge fraction on mechanical alloying in vibratory ball mill

Effect of ball-charge fraction on mechanical alloying in vibratory ball mill

Studies on the effect of ball milling on lignin structure using a modified DFRC method.

The structures of milled wood lignin (MWL), cellulolytic enzyme lignin (CEL), and residual lignin (REL) from a loblolly pine were analyzed using a modified derivatization followed by reductive cleavage (DFRC) method developed to allow the quantitative determination of three different structural monomeric products originating in lignin: phenolic beta-O-4, alpha-O-4, and etherified beta-O-4 structures. Results show that MWL and CEL are structurally identical, with an increased phenolic beta-O-4 content compared to that of the original Wiley milled wood. These results indicate that the portion of lignin linked to carbohydrates and that not linked to carbohydrates are structurally the same. Modified DFRC analysis of the effect of ball milling on the structure of lignin in wood, MWL, CEL, and REL indicate that vibratory ball milling does not change the lignin structure provided certain precautions are taken. Specifically, dry vibratory ball milling under a nitrogen atmosphere causes substantial structural changes including condensation, whereas vibratory ball milling in toluene had little effect on the lignin structure. This indicates that the structural differences observed in MWL and CEL arise because of the extraction procedure, which preferentially extracts phenolic lignin structures. MWL and CEL are representative of the total lignin in wood; however, due primarily to the solvent extraction process, higher phenolic hydroxyl contents are observed. Nitrobenzene oxidation showed structural results similar to those from the modified DFRC method.

Modelling of a steel ball's grade based on image texture features

The quality of steel balls has a substantial influence on bearing performance. The conventional way of measuring steel balls is by examining randomly selected specimens owing to the lack of efficient test methods. However, this cannot guarantee that every individual ball meets a certain standard. The traditional measurement is not acceptable in those fields where stability and reliability are highly demanded. An automatic method to measure a steel ball's quality to make exhaustive examination feasible and efficient was investigated. This paper describes the prediction model of a steel ball's vibration level based on image texture features by regression analysis method. The model establishes the relationship between the surface microscopic image of a steel ball and its vibration level, which is the major criterion to judge the quality of a steel ball. Experimental results have demonstrated that the prediction model approximates the real vibration level very closely. Several fitting models have been tested and a non-linear quadratic prediction model gives rise to the highest fitting precision.

Development of high-speed superplastic Al alloy by the MA process using Al foil

Recently, it has been found that some mechanically alloyed (MA) aluminum alloys exhibit superplasticity at higher strain rates of more than 1 s −1. In general, metallic powders are used as raw materials in the development of superplastic alloys by the MA methods. Powder material is generally more expensive than ingot material MA by vibratory ball mill was conducted using comparatively cheap Al foil material under various milling time conditions. The properties of the MA materials were investigated by tensile tests in several strain rates. As a result, high-speed superplastic material was obtained in a quarter of the milling time and at 16% of the cost required to develop the same qualities using Al powder.