Surface Of Balls Research Articles

Effect of 3D printing modes by ceramics and sintering on shrinkage process of thin-walled parts

Subject of Research. The paper presents the study of 3D printing modes and heat treatment effect of ceramic thin- walled plates with dimensions of 20 × 5 × 40 mm. The relationship is determined between 3D printing, heat treatment and the percentage of shrinkage and surface quality of the obtained ceramic parts. Method. Ceramic parts were created using 3D printing by laser stereolithography. Heat treatment of parts was carried out by dividing the samples into three groups. Each group was located in the furnace in one of the three positions: in a metal box under quartz layer, under a layer of zirconium balls and on the surface of zirconium balls. Main Results. We have compared the surface quality and the shrinkage percentage of the samples, the thickness of the printed layer of 25, 50 and 100 μm and heat-treated under the indicated conditions. An improvement in the surface quality of the samples was found with the decrease in the layer thickness and particle size of the ceramic powder (from the range of 1-5 μm to the range of 0.01-1 μm). The shrinkage percentage of the product decreases by about 2 times with increase in the duration of heat treatment and the percentage of powder in the ceramic suspension. Practical Relevance. The use of new 3D printing modes and improved heat treatment conditions gives the possibility to obtain samples with better surface quality and lower percentage of shrinkage. The proposed technological process of laser stereolithography provides the creation of thin-walled ceramic products of higher quality with high accuracy of geometric dimensions. The results obtained make it possible to use the applied modes and methods for creating ceramic objects in such industries as aircraft manufacturing, radio electronics, medicine and other industries.

ANALYSIS OF RING CRACKS IN CERAMIC ROLLING ELEMENTS USING THE BOUNDARY ELEMENT METHOD

Ceramic materials have been increasingly used in bearing systems for over a dozen years. This is due to the specific properties of ceramic materials, such as high hardness, corrosion resistance, the possibility of use in aggressive chemical environments, as well as due to the lower specific weight as compared to steel materials. However, the use of ceramic materials imposes many limitations. The main disadvantages include surface cracks and a low fracture toughness value. The paper presents a numerical analysis of crack propagation in silicon nitride balls. The directions of propagation were analysed for the cracks that are most commonly found on the surface of the commercially available ceramic balls. The directions were analysed along the crack front and considering the location of the crack in relation to the contact point of the balls in the rolling contact. The numerical calculations are based on a three-dimensional model of the ring crack. Numerical calculations were carried out using the boundary element method. Numerical solutions were compared with the results of experimental research.

Tribological properties of hybrid surface textured GCr15 steel filled by epoxy resin-based material under dry friction

Micro-grooves were fabricated on GCr15 steel disc and filled by epoxy resin composites, formed hybrid laser surface texture. The tribological properties of textured disc sliding against ceramic ball were investigated. The friction tests were carried on a ball-on-disc tribometer. Three kinds of fibers, two kinds of particle and three kinds of polymer were selected to improve the epoxy resin-based material filled in the micro-grooves. Glass fiber (GF), graphite particle (GP) and PTFE shown better tribological performances, which were selected as additives for the optimized design of the epoxy resin composite. The specimen with fill ratio of 3:1:1 (PTFE: GF: GP) exhibits lower friction coefficient and better wear resistance. The worn surface of textured discs and balls were observed. It was found that this hybrid laser surface texture could form a transfer layer on the contact surface, which contribute to the friction and wear reduction of tribo-pairs under dry friction condition.

Preliminary investigations on the tribological performance of hexagonal boron nitride nanofluids as lubricant for steel/steel friction pairs

With laminated structure like graphite, hexagonal boron nitride nanoparticle (nano-hBN) performed excellent anti-wear and friction-reducing properties. In this paper, hBN nanofluids were prepared using sodium polyacrylate (PAAS) as dispersant in water. Four-ball tribometer and pin-on-disk tribometer were employed to evaluate the tribological performance and lubrication behavior of the above-prepared lubricating fluids during steel/steel friction. The worn surface of balls and disks was analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and x-ray photoelectron spectrometer (XPS). The minimum lubricating film thickness was calculated by Hamrock and Dowson equation. Results showed that 0.7 wt% was the optimum concentration of nano-hBN in water which significantly reduced the coefficient of friction (COF) and wear scar diameter (WSD) by about 29% and 15%, respectively. The lubricating film thickness was lower than both nanoparticles diameter and worn surface roughness. From the above it was concluded that the worn area could be divided into direct contact, particle lubricating and liquid lubricating area with rolling mehanism, interlayer sliding mechansim, polishing mechansim and mending mechansim of nanoparticles. A protective film was formed on friction surface by PAAS molecule, FeOOH and FeO due to the absorption effect and tribochemical reaction between the nanofluids and worn surface, which further reduced the friction and wear rate.

Laser Cladding of Ti-Based Ceramic Coatings on Ti6Al4V Alloy: Effects of CeO2 Nanoparticles Additive on Wear Performance

Ti-based ceramic coatings on Ti6Al4V substrates were successfully prepared through a laser cladding process using pre-placed starting materials of TiCN + SiO2 mixed powder without or with adding a 3 wt % CeO2 nanoparticles additive, aiming at improving the wear resistance of the Ti6Al4V alloy for biological applications. The effects of the CeO2 nanoparticles additive on the microstructure, microhardness, and wear performance of the coatings were analyzed in detail. The observations showed that the main compositions of the cladding coating were TiCN and TiN phase. Compared to the coatings without CeO2, the coatings modified with CeO2 nanoparticles led to more excellent mechanical properties. The average microhardness of the coatings modified with CeO2 nanoparticles was approximately 1230 HV0.2, and the wear volume loss of the coatings modified with CeO2 nanoparticles was approximately 14% less than that of the coatings without CeO2 under a simulated body fluid (SBF) lubrication environment. The major reasons included that the microstructure of the coatings modified with CeO2 nanoparticles was refined and compact granular crystalline. The wear mechanisms of the coatings were investigated from the worn surface of the coatings, wear debris, and the worn surface of the counter-body balls. The wear mechanisms of the coatings without CeO2 included abrasive wear, adhesive wear, and fatigue wear, while the wear mechanisms of the coatings modified with CeO2 nanoparticles included only abrasive wear and adhesive wear, because the fine microstructure of the coatings had an excellent resistance to fatigue wear.

Application of Titanium Dioxide (TiO₂)-Embedded Buoyant Photocatalyst Balls Using Expanded Polystyrene.

A new immobilization technique of nanoscale TiO₂ powders to expanded polystryrene (EPS) balls with temperature-controlled melting method was validated for mass production, and the photocatalytic activity of TiO₂ powder-embedded EPS (TiEPS) balls using methylene blue (MB) solution with different concentrations under ultraviolet irradiation and under the natural solar light irradiation. Whereas MB molecules were weakly adsorbed onto the surface of both TiO₂ powders and supporting polymers without any specific interactions, the photocatalytic efficiency of TiEPS balls with UV (Kapp =0.016~0.043 min-1) was greater through coupled reaction processes (adsorption, photolysis, and photocatalysis). After 5-min sonication, more TiO₂ powders on the TiEPS balls can be involved into the both adsorption and photocatalytic reactions of MB, and can increase the MB removal efficiencies. TiEPS balls can be reused for several consecutive runs without any significant decrease in photocatalytic activity until the recalcitrant contaminants were completely coated on the surface of TiEPS balls and loss of TiO₂ powders embedded on the surface of TiEPS balls was significant. Based on the aforementioned results, self-floating TiEPS balls manufactured from this simple and cost-effective melting method can be used to remove the organic contaminants and to inhibit the excessive growth of harmful algae in the stagnant water body.

Development of Titanium Dioxide (TiO₂)-Embedded Buoyant Photocatalyst Balls Using Expanded Polystyrene.

A new immobilization technique of nanoscale TiO₂ powders to expanded polystryrene (EPS) balls with temperature-controlled melting method was developed for mass production, and the characterization of TiO₂ powder-embedded EPS (TiEPS) balls was evaluated. Based on the scanning electron microscope (SEM) images and associated energy-dispersive X-ray spectroscopy (EDX) analysis, the components of intact EPS balls are carbon and oxygen whereas those of TiEPS balls are carbon, oxygen, and titanium, indicating that TiO₂ powders were embedded on the surface of EPS balls. As also evident by the X-ray diffraction (XRD) and FTIR analyses, no significant changes in crystalline structure of TiO₂ powders embedded on the EPS balls were found during the preparation and application processes of TiEPS balls. These characterization results indicated that the patches of TiO₂ powders were soundly impregnated over the surface of EPS balls without the significant changes in crystalline structure of TiO₂ powders and both structural changes and deformation of EPS polymer.

Stable single-atom cobalt as a strong coupling bridge to promote electron transfer and separation in photoelectrocatalysis

In photoelectrochemical water decomposition field, it remains a key challenge to develop photoanodes with excellent charge separation and transfer, efficient solar collection and rapid surface reaction kinetics. Here, we report a new strongly coupled ternary hybrid system using a single atom as a “bridge” to achieve high efficiency water oxidation photoelectrochemical performance, by constructing a monoatomic transition metal tightly bound to the core-shell gap which formed by lamina g-C3N4 coating on the surface of porous carbon balls. Experimental results and density functional theory calculations show that the unique structure combines lots of beneficial features, that is efficient light trapping and photo-generated charge separation, strong coupling effects, fast electron transport paths and improved surface reaction dynamics. Benefited from the ideal nanostructure, the photocurrent density reached 5.08 mA cm−2 at 1.23 V and the IPCE value achieved 27.5% at 350 nm under AM 1.5 G illumination. This work has promoted a significant step of developing single-atom photoanodes with unique structure for solar water splitting, as well as the design of thermochemically stable catalysts.

The wear characteristics of CeO2 containing nanocomposite coating made by aluminate-based PEO on AM 50 magnesium alloy

This study examined the influence of CeO2 nanoparticles on the wear characteristics of aluminate-based PEO coatings formed on the AM50 magnesium alloy, which was developed for the automotive industry. Sliding wear assessments were conducted on a ball-on-disk tribometer at 2 N, 5 N and 10 N loads (against an AISI 52100 steel ball). It was found that the wear characteristics were greatly affected by the addition of CeO2 nanoparticles, especially under intermediate and high loads. The coatings with and without CeO2 remained intact during the sliding test at 2 N. Under an intermediate load of 5 N, the coating treated in the absence of CeO2 failed, while the one made in the presence of CeO2 offered superior wear resistance without any signs of wear failure. Under the 10 N load, the CeO2-free coating was completely removed and the substrate emerged, which was mainly due to a combined adhesive–abrasive wear damage mechanism; in contrast, the CeO2-containing coating (PEO-CeO2) offered much superior wear resistance to the Mg alloy, which was consistent with the friction coefficient data. SEM-EDS analysis of the worn surface of the steel balls also indicated that the transfer of the coating fragments to the ball surface was more intensive for the nanoparticle-free coating, as compared to that observed for the PEO-CeO2 coating. Also, the appearance of some deep scoring in the worn surface of the balls could be considered as a result of the three-body abrasive wear. The superior wear resistance of the CeO2 embedded nanocomposite coating could be mainly attributed to its lower porosity, lower roughness, and higher hardness.

Interaction Mechanisms between Schungite and Friction Surfaces under High-Energy Ball Milling

An effect of schungite exerted on the degradation of surfaces in the processes of friction and wear is studied. The process is simulated via processing a mixture schungite and iron powders using a high-energy ball mill. Changes in the morphology and structural and phase composition of the milled mixture, as well as in the surface of the grinding balls, are investigated. It is shown that the positive effect of schungite addition to lubricating substances is mainly caused by improvement of the surface quality (roughness reduction) of the contacting bodies after mechanical treatment.

Simple mechanics model and Hertzian ring crack initiation strength characteristics of silicon nitride ceramic ball subjected to thermal shock

This study investigated the ring crack initiation strength characteristics of silicon nitride ceramic balls subjected to thermal shock. Sphere indentation tests were conducted on ceramic balls following water quenching and furnace cooling operations performed in air and vacuum. The ring crack radius was significantly smaller because of the very thin silicon oxide (SiO2) layer formed owing to heat treatment in air at high temperatures. In addition, the ring crack initiation load and Weibull shape parameter of water-quenched ceramic balls decreased with increasing temperature difference and remained relatively unaffected by the high-temperature oxidation. This phenomenon was mainly due to microscopic damage, which occurs near the surface of ceramic balls, caused by transient thermal stress developed during water quenching. A simple mechanics model based on the constant energy release rate criterion has been proposed for comparing experimental results obtained in this study against theoretical predictions, and results of the said comparison adequately verify strength characteristics of the aforementioned ceramic balls subjected to thermal shock.

Tribological properties of nano cellulose fatty acid esters as ecofriendly and effective lubricant additives

Three cellulose esters, cellulose acetate-butyrate, cellulose acetate-octanoate, and cellulose acetate-laurate, were synthesized by both conventional co-reactant reaction (CCR) and mechanical activation-assisted co-reactant reaction (MACR) methods, and the corresponding nano-cellulose esters were prepared by high pressure homogenization to comparatively investigate their tribological properties as lubricant additives in liquid paraffin base oil. MACR method was more effective than CCR method for preparing long chain cellulose esters, and the MACR-prepared cellulose esters were more easily homogenized to smaller nanoparticles. Tribological testing indicated that anti-wear and load-carrying properties of the lubricants were significantly enhanced with nano-cellulose esters as additives compared to those of pure liquid paraffin, especially the MACR-prepared long chain cellulose esters. The wear scar diameter on worn surface of the steel balls reduced with the increase in degree of substitution (DS) and chain length of long chain substituents and the decrease in size dimension of nano-cellulose esters. The polar ester carbonyl groups, unesterified hydroxyl groups, and long hydrocarbon alkyl chains in nano-cellulose esters could lead to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear, which gave the lubricants with good anti-wear and load-carrying properties. The nano-cellulose esters with high DS and long chain substituents prepared by MACR technology as ecofriendly additives exhibited better lubricating ability. Nano-cellulose esters with high DS of long chain substituents prepared by mechanical activation-assisted co-reactant reaction technology used as ecofriendly lubricant additives in base oil showed good anti-wear and load-carrying properties, ascribing to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear.

Porosity and Permeability Evolution Induced by Precipitation of Silica under Hydrothermal Conditions

Water-rock interaction provides significant influences on evolution of hydrological properties within the crusts. Especially, dissolution and precipitation of silica in fractures play essential roles on permeability evolution. In this study, we conducted hydrothermal-flow through experiments on silica precipitation within porous media (alumina inner tube packed with alumina balls) for investigating how a fracture is clogged by silica precipitation. We used high Si supersaturated solution for precipitation under vapor (390 °C and 20 MPa) or supercritical condition (420 °C and 30 MPa), and the porosity structure was examined by X-ray CT. Under the vapor condition, fine-grained quartz was nucleated and immediately deposited on the bottom. In contrast, under the supercritical condition, spherical silica particles, which are composed of opal-A, opal-C and quartz, were formed in fluids, transported and covered the surface of alumina balls uniformly. In the latter case, a characteristic fluid pressure (permeability) oscillation was observed; which is probably explained by repeated clogging and break of pore throats.

Dual-Functionalized Theranostic Nanocarriers.

Nanocarriers with the ability to spatially organize chemically distinct multiple bioactive moieties will have wide combinatory therapeutic and diagnostic (theranostic) applications. We have designed dual-functionalized, 100 nm to 1 μm sized scalable nanocarriers comprising a silica golf ball with amine or quaternary ammonium functional groups located in its pits and hydroxyl groups located on its nonpit surface. These functionalized golf balls selectively captured 10-40 nm charged gold nanoparticles (GNPs) into their pits. The selective capture of GNPs in the golf ball pits is visualized by scanning electron microscopy. ζ potential measurements and analytical modeling indicate that the GNP capture involves its proximity to and the electric charge on the surface of the golf balls. Potential applications of these dual-functionalized carriers include distinct attachment of multiple agents for multifunctional theranostic applications, selective scavenging, and clearance of harmful substances.

Current understanding on Villosiclava virens, a unique flower-infecting fungus causing rice false smut disease.

Villosiclava virens (Vv) is an ascomycete fungal pathogen that causes false smut disease in rice. Recent reports have revealed some interesting aspects of the enigmatic pathogen to address the question of why it specifically infects rice flowers and converts a grain into a false smut ball. Comparative and functional genomics have suggested specific adaptation of Vv in the colonization of rice flowers. Anatomical studies have disclosed that Vv specifically infects rice stamen filaments before heading and intercepts seed formation. In addition, Vv can occupy the whole inner space of a spikelet embracing all floral organs and activate the rice grain-filling network, presumably for nutrient acquisition to support the development of the false smut ball. This profile provides a general overview of the rice false smut pathogen, and summarizes advances in the Vv life cycle, genomics and genetics, and the molecular Vv-rice interaction. Current understandings of the Vv-rice pathosystem indicate that it is a unique and interesting system which can enrich the study of plant-pathogen interactions. Taxonomy: Ustilaginoidea virens is the anamorph form of the pathogen (Kingdom Fungi; Phylum Ascomycota; Class Ascomycetes; Subclass Incertae sedis; Order Incertae sedis; Family Incertae sedis; Genus Ustilaginoidea). The teleomorph form is Villosiclava virens (Kingdom Fungi; Phylum Ascomycota; Class Ascomycetes; Subclass Sordariomycetes; Order Hypocreales; Family Clavicipitaceae; Genus Villosiclava). Disease symptoms: The only visible symptom is the replacement of rice grains by ball-shaped fungal mycelia, namely false smut balls. When maturing, the false smut ball is covered with powdery chlamydospores, and the colour changes to yellowish, yellowish orange, green, olive green and, finally, to greenish black. Sclerotia are often formed on the false smut balls in autumn. Identification and detection: Vv conidia are round to elliptical, measuring 3-5 μm in diameter. Chlamydospores are ornamented with prominent irregularly curved spines, which are 200-500 nm in length. The sclerotia are black, horseshoe-shaped and irregular oblong or flat, ranging from 2 to 20 mm. Nested polymerase chain reaction (PCR) and quantitative PCR have been developed to specifically detect Vv presence in rice tissues and other biotic and abiotic samples in fields. Host range: Rice is the primary host for Vv. Natural infection by Vv has been found on several paddy field weeds, including Digitaria marginata, Panicum trypheron, Echinochloa crusgalli and Imperata cylindrica. However, the occurrence of infection in these potential alternative hosts is very rare. Life cycle: Vv infects rice spikelets at the late rice booting stage, and produces false smut balls covered with dark-green chlamydospores. Occasionally, sclerotia form on the surface of false smut balls in late autumn when the temperature fluctuates greatly between day and night. Both chlamydospores and sclerotia may serve as primary infection sources. Rainfall at the rice booting stage is a major environmental factor resulting in epidemics of rice false smut disease. Disease control: The use of fungicides is the major approach for the control of Vv. Several fungicides, such as cuproxat SC, copper oxychloride, tebuconazole, propiconazole, difenoconazole and validamycin, are often applied. However, the employment of resistant rice cultivars and genes has been limited, because of the poor understanding of rice resistance to Vv. Useful websites: Villosiclava virens genome sequence: http://www.ncbi.nlm.nih.gov/Traces/wgs/?val=JHTR01#contigs.

Verification of the Results of Benchmark Experiments on Measuring the Spectra of Neutron Leakage from the Surface of Iron Balls with Radionuclide Sources Placed Inside

At the present time with relation to the development of nuclear power and advancements in computer capabilities, the codes of ionizing radiation field calculation in the design and operation of nuclear power plants and other installations with applied nuclear sources have been improved. It is now feasible to solve complicated three-dimensional problems with more stringent requirements and to refine errors from the results obtained. The libraries of constants of neutron interaction with nuclei of various isotopes used in the calculations as a rule make the most appreciable contribution to refinement of these errors. These libraries take a long time to build, consisting of experimental measurement cross-sections of interactions of neutron with nuclei, their analysis and estimation and, finally, creation of the neutron constants libraries that need final experimental verification. The simplest geometry is chosen for such experiments. For this purpose the materials under investigation are formed in a ball, and small-sized radionuclide sources are used so that they may be modeled in the calculations by point and isotropic sources are located in the center of the balls. The selected geometry of experiments allows the energy distribution of neutron currents from a unit of sphere surface to be fairly reliably measured, and simple codes to be used in order to obtain their calculated values. The reliability of such benchmark experiments is often checked by means of additional calculations of their results with the use of codes and libraries of neutron constants showing good results in practice. The purpose of our work (with the results described in the paper) was a comprehensive substantiation of the results of earlier benchmark experiments on measuring the energy spectra of neutrons escaping from the surface of iron balls because iron is one of the main elements for structural materials used in nuclear power engineering. The benchmark experimental results validated in this way are assumed to be reliably used for the final check of improved or newly created systems of neutron constants.

Responsibility to Protect, Responsibility to Whom?

Sovereignty & the Responsibility to Protect: A New History. By Luke Glanville. Chicago and London: Chicago University Press, 2014. 294 pp., $95.00 hardcover (ISBN-13: 978-0-226-07689-8), $32.50 paperback (ISBN-13: 978-0-226-07692-8). In the natural sciences, it is customary for theories to be tested and retested, falsifiability being one of the touchstones of academic rigor. In the social sciences, by contrast, it is common for ideas to simplify and ossify, with acceptance and repetition degrading them into cliches. So it is with a term like “sovereignty,” which is so loaded with significance that a precise and agreed-upon definition in politics or law has long been dismissed as unlikely. In the absence of such a definition, its use in at least some fields of International Relations (IR) has been reductionist—exemplified by the “billiard ball” model of states that are thought to interact with one another as billiard balls do on a table. Shiny and smooth, the surface of these billiard balls is all that matters to international society, ignorant of and irrelevant to what happens inside. In such a conception of sovereignty, responsibility for how the state is run lies with the sovereign alone. “L'etat,” as Louis XIV may or may not have said, “c'est moi.” Wielding not a cue but a hammer, Luke Glanville successfully demolishes this caricature in his historical survey of sovereignty, building on a doctoral thesis supervised by Alex Bellamy and Richard Devetak. His argument, which extends back to the emergence of sovereignty in early modern Europe, is that sovereignty has always entailed aspects of responsibility as well as authority. Glanville's more specific aim is to challenge the idea that there is anything “new” about the most recent perceived challenge to the “traditional” conception of sovereignty: the responsibility to protect. This doctrine emerged from the aftermath of the 1999 Kosovo intervention and comprises two key principles that were embraced by all members of the United Nations in 2005: first, …

A study on tribological behaviours of ZDDP in polymer thickened lubricating greases

Zinc Dialkyl Dithiophosphate (ZDDP) is a well-known multifunctional additive for soap based lubricating greases. Polymers are being studied for their performance as lubricating grease thickeners and rheology modifiers. In this work the tribological study of ZDDP was carried out in polypropylene (PP), maleated polypropylene (mPP) and linear low density polyethylene (PE) thickened lubricating greases. Performance of lithium grease was taken as a reference. The tribological properties were evaluated using a four ball tester for EP properties and Optimol SRV-III machine for coefficient of friction. The mechanism of action of ZDDP in polymer greases was established through analysis of the worn surface of steel balls with scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDAX). The results show that the performance of ZDDP depends on the thickener system. The antiwear and EP property exhibited by ZDDP varies from polymer to polymer. Poor performance was observed with PP type thickener whereas performance in PE and lithium grease was comparable. Copyright © 2015 John Wiley & Sons, Ltd.

Responsibility to Protect, Responsibility to Whom?

In the natural sciences it is customary for theories and concepts to be tested and retested, falsifiability being one of the touchstones of academic rigour. In the social sciences, by contrast, it is common for ideas to simplify and ossify, with acceptance and repetition degrading them into cliches. So it is with a term like “sovereignty”, which is so loaded with significance that a precise and agreed definition in politics or law has long been dismissed as unlikely. In the absence of such a definition, its use in at least some fields of international relations has been reductionist — exemplified by the “billiard ball” model of states that are thought to interact with one another as billiard balls do on a table. Shiny and smooth, the surface of these billiard balls is all that matters to international society, ignorant of and irrelevant to what happens inside. Sovereignty in this conception is antithetical to the idea of responsibility to anyone but the sovereign. “L’etat,” as Louis XIV may or may not have said, “c’est moi.”Wielding not a cue but a hammer, Luke Glanville successfully demolishes this caricature in an impressive historical survey of sovereignty, building on a doctoral thesis supervised by Alex Bellamy and Richard Devetak. His argument, which extends back to the emergence of sovereignty in early modern Europe, is that sovereignty has always entailed aspects of responsibility as well as authority.

Investigation of Controllable Parameters of Mechanical Treatment on Aluminum-Based Composite in Marine Application

Surface Mechanical Attrition Treatment (SMAT) process, as one of the typical severe plastic deformation technologies, can be utilized to generate layup structure with finer size of grains and large residual stresses at the near treated surface area on the alloys. Such technology not only improves the mechanical behaviors but also keeps neatness of alloys without inducing extra compositions. In this paper, four major controllable parameters of SMAT process are investigated to demonstrate their influence on ball-impacting intensity of the treatment, which the improvement of mechanical behaviors are greatly dependent on. The high speed camera is employed to capture the motion of the balls and measure the impact velocities by counting the number of frames. The compared results indicate that the amount of balls not only varies the average velocities during SMAT process, but also offsets the effect of distance between treated surface and source of balls. In addition, the influence of ball sizes, the mentioned distance and power of excitation exhibits apparently on intensity of SMAT process when limited amount of balls are used.