The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
B. Mohan - One of the best experts on this subject based on the ideXlab platform.
-
Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite
Journal of Materials Processing Technology, 2006Co-Authors: S. Balasivanandha Prabu, L. Karunamoorthy, Sekar Kathiresan, B. MohanAbstract:In the present study, high silicon content aluminium alloy-silicon carbide metal matrix composite material, with 10%SiC were successfully synthesized, using different stirring speeds and stirring times. The microstructure of the produced composites was examined by optical microscope and scanning electron microscope. The Brinell Hardness Test was performed on the composite specimens from base of the cast to top. The results revealed that stirring speed and stirring time influenced the microstructure and the Hardness of composite. Microstructure analysis revealed that at lower stirring speed with lower stirring time, the particle clustering was more. Increase in stirring speed and stirring time resulted in better distribution of particles. The Hardness Test results also revealed that stirring speed and stirring time have their effect on the Hardness of the composite. The uniform Hardness values were achieved at 600 rpm with 10 min stirring. But beyond certain stir speed the properties degraded again. An attempt is made in this study to establish the trend between processing parameters such as stirring speed and stirring time with microstructure and Hardness of composite. © 2005 Elsevier B.V. All rights reserved.
Sven Bengtsson - One of the best experts on this subject based on the ideXlab platform.
-
an application of universal Hardness Test to metal powder particles
Journal of Materials Processing Technology, 2009Co-Authors: Eduard Hryha, Pavel Zubko, Eva Dudrova, Ladislav Pesek, Sven BengtssonAbstract:Powder metallurgy is a “net shape” components producing technology from metal powders by compaction with following sintering processes. For today actual trends of powder metallurgy are associated with modern powder grades, alloyed by elements with high affinity to oxygen (Cr, Mn, Si, etc.). Contamination of powder particles by oxides and/or other secondary phases have a negative effect on their compressibility and sinterability. The geometry properties of powders give integral information about powder quality. Evaluation of yield strength and/or rather the strain hardening exponent, characterizing the mechanical properties on the level of individual particles, really is not possible. One of available approaches could be measurement of the microHardness of particles. The contribution deals with the evaluation of the microHardness of powder particles and specification of the factors affecting measured values. Using standard Vickers microHardness HV0.01 measurements for two different powders the results obtained showed large scattering from the average. This gave no possibility to identify the influence of alloying and particle matrix purity on microHardness. Problem was solved utilizing instrumented indentation Test using NanoIndenter XP. This is usable technique for estimation of microHardness of powder particle matrix and gives possibility to recognize differences between different size fractions of particles. Based on the obtained results it was concluded, that absolute results of indentation Hardness and indentation modulus are strongly affected by mounting resin type. Utilizing DSI method and mounting resin of proper Hardness enabled to evaluate the microHardness of powders with different alloying element content. Influence of particles purity/size on powder microHardness was established as well. Indentation Hardness and indentation modulus for sintered materials are in good agreement with the data for corresponding bulk materials. Obtained results confirm that universal Hardness Test is valuable instrument for evaluating of sintered materials properties.
Yanli Song - One of the best experts on this subject based on the ideXlab platform.
-
characterization of the inhomogeneous constitutive properties of laser welding beams by the micro vickers Hardness Test and the rule of mixture
Materials & Design, 2012Co-Authors: Yanli SongAbstract:Abstract A novel approach has been proposed to characterize the inhomogeneous mechanical properties of weld materials by using the micro-Vickers Hardness Test combined with the rule of mixture. This proposed method has introduced the influences of the inhomogeneous properties of weld materials by considering the variations in plastic behaviour across the weld cross-section. The inhomogeneous properties of laser welding beams for tailor welded blanks (TWBs), which were three different types of combinations of DX56D and DP600 automotive steel sheets, were extracted by using this proposed method. The instrumented indentation Tests were conducted to verify the measured inhomogeneous properties of weld materials. The fact that the calculated true stress–strain curves agreed well with the experimental ones has confirmed the reliability and accuracy of the proposed method.
Hisao Matsunaga - One of the best experts on this subject based on the ideXlab platform.
-
hydrogen distribution of hydrogen charged nickel analyzed via Hardness Test and secondary ion mass spectrometry
International Journal of Hydrogen Energy, 2020Co-Authors: Junichiro Yamabe, Kentaro Wada, Tohru Awane, Hisao MatsunagaAbstract:Abstract The hydrogen compatibility of metallic materials is often evaluated by conducting tensile Tests of H-charged specimens in air or inert gas at ambient temperature; however, it is not clear whether the H distribution calculated with hydrogen diffusivity under a diffusion-controlled process is consistent with the actual distribution. This study estimated the hydrogen distribution in a H-charged nickel maintained in air at ambient temperature for a few months after exposure to hydrogen gas by using the Vickers Hardness Test and secondary ion mass spectrometry. Both methods provided similar H distributions, which were fitted by the solution of a diffusion equation under a diffusion-controlled process, and the hydrogen diffusivity was also determined. The estimated H distributions were successfully fitted by the solution of the diffusion equation, and the determined hydrogen diffusivity of nickel was consistent with literature data, indicating that the calculated H distribution reproduced the actual one.
Dietmar Eifler - One of the best experts on this subject based on the ideXlab platform.
-
cyclic Hardness Test phybalcht a new short time procedure to estimate fatigue properties of metallic materials
International Journal of Fatigue, 2014Co-Authors: Hendrik Kramer, Marcus Klein, Dietmar EiflerAbstract:Conventional methods to characterize the fatigue behavior of metallic materials are very time and cost consuming. That is why the new short-time procedure PHYBALCHT was developed at the Institute of Materials Science and Engineering at the University of Kaiserslautern. This innovative method requires only a planar material surface to perform cyclic force-controlled Hardness indentation Tests. To characterize the cyclic elastic-plastic behavior of the Test material the change of the force-indentation-depth-hysteresis is plotted versus the number of indentation cycles. In accordance to the plastic strain amplitude the indentation-depth width of the hysteresis loop is measured at half minimum force and is called plastic indentation-depth amplitude. Its change as a function of the number of cycles of indentation can be described by power-laws. One of these power-laws contains the hardening-exponentCHT e II , which correlates very well with the amount of cyclic hardening in conventional constant amplitude fatigue Tests.
