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Fuang-yuan Huang - One of the best experts on this subject based on the ideXlab platform.
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examination of wire electrical discharge machining of al2o3p 6061al composites
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Hsien Chung Tsai, Fuang-yuan HuangAbstract:Abstract Alumina Particle reinforced 6061 aluminum matrix composites (Al2O3p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al2O3p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al2O3p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking. The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al2O3 Particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al2O3p/6061Al composite are easily formed, basically due to some embedded reinforcing Al2O3 Particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al2O3p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness.
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examination of wire electrical discharge machining of al2o3p 6061al composites
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Biinghwa Yan, Hsien Chung Tsai, Fuang-yuan Huang, Long Chorng LeeAbstract:Abstract Alumina Particle reinforced 6061 aluminum matrix composites (Al2O3p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al2O3p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al2O3p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking. The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al2O3 Particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al2O3p/6061Al composite are easily formed, basically due to some embedded reinforcing Al2O3 Particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al2O3p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness.
Kexing Song - One of the best experts on this subject based on the ideXlab platform.
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optimization of the processing parameters during internal oxidation of cu al alloy powders using an artificial neural network
Materials & Design, 2005Co-Authors: Bao Hong Tian, Ping Liu, Kexing Song, Jiandong Xing, Qiming Dong, Xianjie CaoAbstract:Internal oxidation is a commercial method for producing oxide dispersion strengthened copper (ODS Cu). In this paper, the dilute Cu–Al alloy powders containing 0.26 wt% of Al have been internally oxidized at temperatures (T) from 700 to 1000 °C, for holding times (t) up to 10 h. The Alumina Particle size has been observed and determined by electron microscopy using the two-stage preshadowed carbon replica method. By the use of backpropagation network, the non-linear relationship between internal oxidation process parameters (T,t) and Alumina Particle size has been established on the base of dealing with the experimental data. The results show that the well-trained backpropagation neural network can predict the Alumina Particle size during internal oxidation precisely and the prediction values have sufficiently mined the basic domain knowledge of internal oxidation process. Therefore, a new way of optimizing process parameters has been provided by the authors.
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internal oxidation of dilute cu al alloy powers with oxidant of cu2o
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2004Co-Authors: Bao Hong Tian, Ping Liu, Kexing Song, Jiandong Xing, Qiming Dong, Xianjie CaoAbstract:Abstract The mechanisms responsible for the nucleation, growth and coarsening of Al2O3 Particles in dilute Cu–Al alloys during internal oxidation have been investigated, and the Alumina morphologies produced have been studied by electron microscopy using two-stage preshadowed carbon replica method. The Alumina Particle size has been observed to increase with increasing temperature of oxidation, with increasing time of oxidation, and with decreasing oxygen resource coefficient over the experimental range. These results indicate that the Alumina Particle size is determined by a competition between the rate of nucleation as the internal oxidation front passes and the subsequent growth and coarsening rates of the Particles.
Garry J P Fleming - One of the best experts on this subject based on the ideXlab platform.
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testing rate and cementation seating load effects on resin strengthening of a dental porcelain analogue
Journal of Dentistry, 2013Co-Authors: Paul Hooi, Owen Addison, Garry J P FlemingAbstract:a b s t r a c t Objectives: To determine the resin-strengthening dependence of a soda-lime-glass analogue for dental porcelain as a function of biaxial flexure strength (BFS), test crosshead rate and cementation seating load. Methods: Disc-shaped soda-lime glass specimens were divided into twelve groups (n = 24), Alumina Particle air abraded and hydrofluoric acid-etched. Specimens (Groups A‐D) were stored in a desiccator prior to testing at crosshead rates of 0.01, 0.1, 1 and 10 mm/min, respectively. The remaining specimens were silane treated, Rely-X Veneer resin-coated with a seating load of 5 N (Groups E‐H) and 30 N (Groups I‐L) prior to light irradiation at 480 � 20 mW/cm 2 , 24 h dry storage and BFS testing at 0.01, 0.1, 1 and 10 mm/min, respectively. A linear logarithmic regression curve was fit to the raw data to elucidate static fatigue effects of the soda-lime-glass. Analysis of group means was performed utilising a general linear model univariate analysis and post hoc all paired Tukey tests (P < 0.05). Results: The linear logarithmic regression curve demonstrated the static fatigue effects of the soda-lime-glass analogue. Rely-X Veneer resin-coating (Groups E‐L) resulted in significant increases in the mean BFS data for all crosshead rates examined (all P < 0.001). However, the pattern of rate dependence effects on resin-cementation deviated from the log relationship observed with the uncoated controls. Conclusion: This study further highlights that when slow crack growth is simulated during testing, valuable insights into the significant modification of a hereto well described phenomenon such as resin-strengthening mediated by the resin‐ceramic hybrid layer is provided.
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the influence of resin flexural modulus on the magnitude of ceramic strengthening
Dental Materials, 2012Co-Authors: Garry J P Fleming, Paul Hooi, Owen AddisonAbstract:Abstract Introduction The aim was to determine the magnitude of ceramic resin-strengthening with resin-based materials with varying flexural moduli using a regression technique to assess the theoretical strengthening at a ‘zero’ resin-coating thickness. The hypothesis tested was that experimentally, increasing resin flexural modulus results in increased resin-strengthening observed at a theoretical ‘zero’ resin-coating thickness. Method Vitadur Alpha dentin porcelain disk (n = 250) were condensed, fired, Alumina Particle air abraded and randomly assigned into ten groups. Groups were resin-coated at 50, 100 and 150 μm with Venus Flow, Rely-X Veneer and Clearfil AP-X before biaxial flexure testing at 24 h and the stress at failure calculated using a multilayer analysis. An analytical methodological approach was undertaken to predict the biaxial flexure stresses under boundary conditions that reflected the experimental test and a finite element model was used to verify the analytical prediction. Results The magnitude of resin-reinforcement was significantly influenced by resin-coating type (P Significance Experimentally, the flexural modulus and thickness of resin-based material used to cement DBC or PLV restorations have a significant impact on the magnitude of resin-strengthening observed. However, for resin-based materials with different flexural moduli the variability in the relationships between thickness and observed increases in biaxial flexure strength of the ceramic requires careful characterization to optimize clinical performance.
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effects of surface finishing conditions on the biocompatibility of a nickel chromium dental casting alloy
Dental Materials, 2011Co-Authors: Emma Louise Mcginley, David C Colema, Gary P Mora, Garry J P FlemingAbstract:Abstract Objectives To assess the effects of surface finishing condition (polished or Alumina Particle air abraded) on the biocompatibility of direct and indirect exposure to a nickel–chromium (Ni–Cr) d.Sign ® 10 dental casting alloy on oral keratinocytes. Biocompatibility was performed by assessing cellular viability and morphology, metabolic activity, cellular toxicity and presence of inflammatory cytokine markers. Methods Discs of d.Sign ® 10 were cast, Alumina Particle air abraded and half were polished before surface roughness was determined by profilometry. Biocompatibility was assessed by placing the discs directly or indirectly (with immersion solutions) into contact with TR146 monolayers. Metal ion release was determined by ICP-MS. Cell viability was assessed by trypan blue dye exclusion, metabolic activity by XTT and cellular toxicity by LDH. Inflammatory cytokine analysis was performed using sandwich ELISAs. Results The mean polished Ra value was significantly reduced ( P Significance Finishing condition of the Ni–Cr dental alloy investigated has important clinical implications. The approach of employing cell density and morphology, metabolic activity, cellular toxicity levels and inflammatory marker responses to TR146 epithelial cells combined with ICP-MS afforded the authors an increased insight into the complex processes dental alloys undergo in the oral environment.
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the deformation and strength of a dental ceramic following resin cement coating
Journal of Dentistry, 2011Co-Authors: G Isgro, Owen Addison, Garry J P FlemingAbstract:Abstract Objectives The hypothesis tested was that processing, pre-cementation and cementation techniques can modify the profilometrically measured deformation of a ceramic. Methods Three-point flexural moduli of a resin-cement were characterised following light irradiation at 430 and 180 mW cm−2. Thirty IPS e.max Ceram discs were prepared and a reference surface produced by polishing. Discs were annealed, Alumina Particle air abraded and resin-coated. Profilometric evaluation was performed following each pre-cementation or cementation operative technique using a contact diamond stylus profilometer. Bi-axial flexure strength of the resin-coated discs, light irradiated at 430 and 180 mW cm−2 (Groups A and B), and the un-coated discs (Group C) was determined. Data were analysed by a one-way analysis of variance with post hoc Tukey tests (P Results Annealing (at 510 °C for 40 min) resulted in a significant reduction (P Conclusion The results of the profilometric technique in combination with the strength supported a strengthening mechanism sensitive to shrinkage stress generation associated with the polymerisation of resin-cements.
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the impact of modifying Alumina air abrasion parameters on the fracture strength of a porcelain laminate restorative material
Dental Materials, 2007Co-Authors: Owen Addison, P M Marquis, Garry J P FlemingAbstract:Abstract Objectives The modification of the “fit” surface of porcelain laminate veneer restorations in order to improve adhesion prior to cementation is often indiscriminate. As a consequence, the surface flaw distribution which is implicated in the probability of failure of the restoration is likely to be dramatically modified. The purpose of the current study was to examine the impact of different air abrasion surface treatments on the bi-axial flexure strength and surface roughness of a porcelain restorative material. Methods Sets of 30 Vitadur-Alpha dentin porcelain discs (15 mm diameter, 0.9 mm thickness) were Alumina abraded with three different grades of Alumina Particle (25, 50 and 110 μm), utilizing two different air stream pressures (35 and 70 psi) and two distinct angles of incidence of Particle delivery (45° and 90°). Mean bi-axial flexure strengths, standard deviations, the associated Weibull moduli (m) and characteristic stress were determined using bi-axial flexure (ball on ring). Results A univariate general linear analysis of means revealed a significant difference between the mean bi-axial flexure strength values of the control group and those of groups subjected to Alumina Particle air abrasion. Further significance ( P Conclusions Alumina Particle air abrasion has a significant degradative effect on the bi-axial flexure strength of the porcelain disc-shaped specimens. Variation of Alumina size, delivery pressure and angle of Particle delivery all impacted on the degree of strength reduction and the shape of the survival probability distributions. It is suggested that Alumina Particle air abrasion acts to remove/modify the initial flaw distribution replacing it with flaws of differing geometry and stability. The premature failure of porcelain laminate restorations may be markedly influenced by Alumina Particle air abrasion depending upon the size and distribution of the crystalline phase present in different dentine porcelains materials used in construction of the restoration.
M.-h. Zhu - One of the best experts on this subject based on the ideXlab platform.
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the effect of Alumina Particle on improving adhesion and wear damage of wheel rail under wet conditions
Wear, 2016Co-Authors: X Cao, Qing Yang Liu, C. G. He, Wen Jian Wang, W.-l. Huang, Junqi Peng, Jun Guo, M.-h. ZhuAbstract:Abstract The objective of this study was to explore the effect of Alumina Particle on improving adhesion and wear damage of wheel/rail under wet conditions using a rolling–sliding wear apparatus. The results indicate that Alumina Particles significantly improve adhesion coefficient under wet conditions. The adhesion coefficient declines with the Alumina Particle size increasing from S (about 75 μm) to L (about 250 μm) and then keeps stable. Meanwhile, the adhesion coefficient increases firstly with the feed rate increasing from 1 to 3 g/min, and then decreases from 3 to 7 g/min, subsequently, keeps stable to 10 g/min. With an increase in Particle size and feed rate, the wear rates of wheel/rail rollers increase, the thickness of plastic deformation layers and surface hardness decrease, and the damage mechanism turns from slight spalling to severe spalling and big pit. The embedded Alumina Particles on the roller surface produce high stress and change the plastic deformation line. Fatigue cracks develop from the surface and the wall of the pit on the rollers, and tend to connect with each other resulting in the removal of material. Furthermore, the interlayer material in the severe cracks tends to break.
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influence of friction modifiers on improving adhesion and surface damage of wheel rail under low adhesion conditions
Tribology International, 2014Co-Authors: Wen Jian Wang, Qing Yang Liu, T F Liu, M.-h. Zhu, Hengyu Wang, X S JinAbstract:The objective of this study is to investigate the influence of friction modifiers on improving adhesion and surface damage of wheel/rail under low adhesion conditions. The results indicate that water, oil and leaves are very easy to bring low adhesion phenomena. Sand, Alumina Particle and abrasive block can improve adhesion coefficient under various low adhesion conditions. Sanding significantly aggravates wear and surface damage of wheel/rail materials. It is proposed that Alumina Particles are more suitable for improving adhesion of wheel/rail interface based on a comprehensive analysis of experimental results.
Hsien Chung Tsai - One of the best experts on this subject based on the ideXlab platform.
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examination of wire electrical discharge machining of al2o3p 6061al composites
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Hsien Chung Tsai, Fuang-yuan HuangAbstract:Abstract Alumina Particle reinforced 6061 aluminum matrix composites (Al2O3p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al2O3p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al2O3p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking. The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al2O3 Particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al2O3p/6061Al composite are easily formed, basically due to some embedded reinforcing Al2O3 Particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al2O3p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness.
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examination of wire electrical discharge machining of al2o3p 6061al composites
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Biinghwa Yan, Hsien Chung Tsai, Fuang-yuan Huang, Long Chorng LeeAbstract:Abstract Alumina Particle reinforced 6061 aluminum matrix composites (Al2O3p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al2O3p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al2O3p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking. The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al2O3 Particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al2O3p/6061Al composite are easily formed, basically due to some embedded reinforcing Al2O3 Particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al2O3p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness.