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Dry sliding tribological behavior of AZ31-WC nano-composites

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Journal of Magnesium and Alloys 2019年第2期7卷 315-327页

作者： Sudip Banerjee Suswagata Poria Goutam Sutradhar prasanta sahoo Department of Mechanical Engineering Jadavpur UniversityKolkata 700032India

The present study investigates the effect of WC nano-particles on tribological behavior of magnesium based nanocomposites for varying wt%of WC(0.5,1,1.5 and 2 wt%).Nanocomposites are fabricated using ultrasonic vibration assisted stir casting *** microscopy,scanning electron microscopy and energy dispersive x-ray patterns are used to characterize the base alloy and fabricated *** values of as-cast composites are obtained through Vicker’s micro-hardness *** and wear behavior of fabricated composites are studied using pin-on-disk type tribotester at room temperature under dry sliding *** load range is 10-40 N while sliding speed range is 0.1-0.4 m/*** of Mg-composites confirms particle inclusion as well as better microstructural integrity with increase in *** value of composites increases with increase in the amount of WC *** and friction behavior of base matrix are also enhanced due to incorporation of WC *** wear mechanisms occurring at the contact surfaces are ascertained through SEM images and EDAX *** in the tested surface is also identified through SEM and *** yields better tribological behavior in composites.

关键词： Mg-WC nanocomposites Ultrasonic vibration Stir-casting Wear Friction

Phenomenological modelling of flow behaviour of 20MnMoNi55 reactor pressure vessel steel at cryogenic temperature with different strain rates

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Defence Technology（防务技术） 2019年第3期15卷 326-337页

作者： Swagatam Paul Partha Dey Snehasish Bhattacharjee Sanjib Kumar Acharyya prasanta sahoo Jayanta Chattopadhyay Department of Mechanical Engineering Jadavpur University Kolkata India Department of Mechanical Engineering Academy of Technology Hooghly West Bengal India Bhaba Atomic Research Centre Mumbai India

In the present study a phenomenological constitutive model is developed to describe the flow behaviour of 20MnMoNi55 low carbon reactor pressure vessel (RPV) steel at sub-zero temperature under different strain rates. A set of uniaxial tensile tests is done with the variation of strain rates and temperature ranging from 10^-4s^-1 to 10^-1s^-1 and -80℃ to 140℃ respectively. From the experimental data, family of flow curves at different temperatures and strain rates are generated and fitted exponentially. The strain rate and temperature dependence of the coefficients of the exponential flow curves are extracted from these curves and characterised through a general phenomenological constitutive coupled equation. The coefficients of this coupled equation are optimised using genetic algorithm. Finite element simulation of tensile tests at different strain rates and temperatures are done using this coupled equation in material model of Abaqus FEA software and validated with experimental results. The novelties of proposed model are:(a) it can predict precisely the flow behaviour of tensile tests (b) it is a simple form of equation where fitting parameters are both function of strain rate ratio and temperature ratio,(c) it has ability to characterize flow behaviour with decreasing subzero temperatures and increasing strain rates.

关键词： Flow behaviour RPV steel Cryogenic temperature Strain rate

A Finite Element Study of Elastic-Plastic Hemispherical Contact Behavior against a Rigid Flat under Varying Modulus of Elasticity and Sphere Radius

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Engineering（科研） 2010年第4期2卷 205-211页

作者： prasanta sahoo Biplab Chatterjee 不详

The present study considers a finite element analysis of elastic-plastic axi-symmetric hemispherical contact for a frictionless deformable sphere pressed by a rigid flat. The material of the sphere is modeled as elastic perfectly plastic. Analysis is carried out to study the effect of varying modulus of elasticity and sphere radius in wide range of dimensionless interference until the inception of plasticity as well as in plastic range. Results are compared with previous elastic-plastic models. It is found that materials with Young’s modulus to yield strength (E/Y) ratio less than and greater than 300 show strikingly different contact phenomena. The dependency of E on dimensionless interference at which the plastic region fully covers the surface is observed. However with different radius, finite element study exhibits similar elastic-plastic phenomena.

关键词： Elastic-plastic Contact Sphere against Flat ANSYS Modulus of Elasticity Sphere Radius

Study of Potentiodynamic Polarization Behaviour of Electroless Ni-B Coatings and Optimization using Taguchi Method and Grey Relational Analysis

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Journal of Minerals and Materials Characterization and Engineering 2011年第14期10卷 1307-1327页

作者： Suman Kalyan Das prasanta sahoo Department of Mechanical Engineering Jadavpur University Kolkata 700032 India

Electroless nickel coatings are very popular for their corrosion resistant actions. The present article attempts to study the corrosion behaviour of electroless Ni-B coatings by varying the coating parameters viz. bath temperature, reducing agent concentration and nickel source concentration together with the annealing temperature. The electrochemical parameters viz., corrosion potential and corrosion current density are evaluated with the help of potentiodynamic polarization experimentation. Taguchi based Grey analysis is employed in order to optimize this multiple response problem and the optimal combination of parameters for maximum corrosion resistance for Ni-B coatings is presented. Moreover, analysis of variance reveals that bath temperature and concentration of nickel source have significant influence on the corrosion performance of the coating. The microstructure characterization of the coating is also conducted with the help of scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction analysis. The Ni-B coating in general exhibits a nodular structure and turns crystalline with heat treatment. The corroded surface exhibits cracks and black spots which imply the occurrence of localized corrosion.

关键词： Electroless coatings Ni-B Corrosion Grey Taguchi.

Wear Behaviour of Al-SiCp Metal Matrix Composites and Optimization Using Taguchi Method and Grey Relational Analysis

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Journal of Minerals and Materials Characterization and Engineering 2012年第11期11卷 1085-1094页

作者： Shouvik Ghosh prasanta sahoo Goutam Sutradhar Department of Mechanical Engineering Jadavpur University Kolkata India

Aluminium metal matrix composite is a relatively new material that has proved its position in automobile, aerospace and other engineering design applications due to its wear resistance and substantial hardness. Need for improved tribological performance has led to the design and selection of newer variants of the composite. The present investigation deals with the study of wear behaviour of Al-SiCp metal matrix composite for varying reinforcement content, applied load, sliding speed and time. Aluminium metal matrix composites reinforced with SiC particles are prepared by liquid metallurgy route using LM6 aluminium alloy and silicon carbide particles (size ~ 37 μm) by varying the weight fraction of SiC in the range of 5% - 10%. The material is synthesized by stir casting process in an electric melting furnace. The materials are then subjected to wear testing in a multitribotester using block on roller configuration. A plan of experiments based on L27 Taguchi orthogonal array is used to acquire the wear data in a controlled way. An analysis of variance is employed to investigate the influence of four controlling parameters, viz., SiC content, normal load, sliding speed and sliding time on dry sliding wear of the composites. It is observed that SiC content, sliding speed and normal load significantly affect the dry sliding wear. The optimal combination of the four controlling parameters is also obtained for minimum wear. The microstructure study of worn surfaces indicates nature of wear to be mostly abrasive.

关键词： Metal Matrix Composite Al-SiCp Wear Optimization Grey-Taguchi

Effect of lanthanum,neodymium on piezoelectric,dielectric and ferroelectric properties of PZT

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Journal of Advanced Ceramics 2013年第1期2卷 37-41页

作者： Benudhar sahoo prasanta Kumar PANDA Materials Science Division CSIR-National Aerospace LaboratoriesKodihalliP.B.No.1779Bangalore 560017India

The effect of La^(3+)and Nd^(3+)on piezoelectric,dielectric and ferroelectric properties of PZT(Pb(Zr_(0.53)Ti_(0.47))O_(3))was *** powders were prepared by“wet-chemical”route followed by calcination at 800℃for 4 *** analysis of the calcined powders confirms the tetragonal phase in the undoped PZT,which gradually decreases with the dopant concentration and the appearance of rhombohedral phase *** study of sintered pellets reveals the decrease in grain size with the increase in dopant concentration beyond 0.02 mol Nd^(3+)and 0.03 mol La^(3+)*** piezoelectric constant(d_(33))and dielectric properties were maximum for 0.02 mol Nd^(3+)and 0.03 mol La^(3+)*** remnant polarization of La^(3+)-doped sample was higher than Nd^(3+)-doped sample,and the sample with combined dopants shows intermediate remnant polarization(P_(r)).Based on the above study,it is concluded that La^(3+)is more effective than Nd^(3+),including in a mixture of La^(3+)and Nd^(3+)dopants.

关键词： lead zirconate titanate wet-chemical piezoelectric dielectric ferroelectric

Synthesis and characterization of manganese tetroxide(Mn_(3)O_(4))nanofibers by electrospinning technique

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Journal of Advanced Ceramics 2013年第1期2卷 26-30页

作者： Benudhar sahoo prasanta Kumar PANDA Materials Science Division CSIR-National Aerospace LaboratoriesKodihalliP.B.No.1779Bangalore 560017India

Manganese tetroxide(Mn_(3)O_(4))nanofibers were prepared by electrospinning homogeneous viscous solution of 20 wt%,28 wt%and 36 wt%manganese acetate in poly vinyl alcohol(PVA)and calcining the nanofibers at 1000℃for 2 *** was carried out at 9 kV DC with tip to collector distance(TCD)of 7 *** gravimetric analysis(TGA)of the fibers indicates the pure phase of manganese oxide above 500℃.XRD analysis of calcined(at 1000℃)nanofibers indicates the formation of phase-pure tetragonal Mn_(3)O_(4).Scanning electron microscopy(SEM)studies show the fibers cylindrical with the diameters in the range of 100-600 nm and aspect ratio>*** general,the average diameter of the green fibers decreases with the increase in manganese acetate *** diameter of calcined nanofibers is reduced by 34%.

关键词： electrospinning manganese tetroxide poly vinyl alcohol nanofiber

Effect of Zr^(4+)on piezoelectric,dielectric and ferroelectric properties of barium calcium titanate lead-free ceramics

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Journal of Advanced Dielectrics 2021年第6期11卷 23-31页

作者： prasanta Kumar Panda Benudhar sahoo V.Sureshkumar Ekaterina Dmitrievna Politova Materials Science Division CSIR-National Aerospace Laboratories KodihalliBengaluru 560017India Semenov Federal Research Centre for Chemical Physics Russian Academy of Sciences Kosygin 4Moscow 119991Russia

Ba_(0.85)Ca_(0.15)(Ti1−xZrx)O_(3)(BCTZ)ceramics with x=0.05,0.10,_(0.15),0.20,0.25,0.30 were prepared by the solid-state reaction *** of the powders was carried out at 1100°C for 4 h and the green pellets were sintered at 1400°C for 2 h.X-ray diffraction patterns of the sintered pellets showed tetragonal splitting up to x=0.10 while the mixture of the rhombohedral/cubic phase appeared at higher ZrO_(2)*** piezoelectric charge constant d33=510 pC/N and strain(S=0.103%)were measured for BCT doped by 0.10 mol ZrO_(2).Dielectric constant,remnant polarization and saturation polarization also found maxima for this *** Curie temperature(TC)of the compositions decreased with increase in ZrO_(2)concentration and reached 98°C,87°C and 36°C at x=0.05,0.10,_(0.15)mol,*** remaining compositions have TC below the room temperature;therefore,they can be used for subzero/cryogenic *** scanning electron microscopy study revealed an increase in grain size with increase in ZrO_(2)concentration and confirmed the complete solubility of ZrO_(2)in the crystal ***,low ZrO_(2)-doped BCT compositions with high d33 could be suitable for low temperature(<80°C)applications.

关键词： ZrO_(2)-doped BCT lead-free piezoelectrics high piezoelectric charge constant Curie temperature