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M. Kawiak and J. Nowacki

Abstract

The cellular structure and unique properties of aluminum foams are the reason of problems concerning their cutting and bonding. The content of the paper includes characterization of the essence of properties and application of aluminum foams, limitations and chances of aluminum foams soldering. The aim of the research is consideration of possibilities and problems of soldering AlSi foams and AlSi - SiC composite foams as well as mechanical properties. The possibility of soldering AlSi foams and AlSi - SiC composite foams using ZnAl solders was confirmed and higher tensile strength of the joint than the parent material was ascertained

Open access

B. Leszczyńska-Madej, A. Wąsik and M. Madej

Abstract

A conventional powder metallurgy method (PM) was used to produce Al-SiC and Al4Cu alloy matrix composites with 2.5, 5, 7.5 and 10 wt% of SiC particles. Two different sizes of the reinforcing phase particles were applied to determine their effect on composite microstructure. The sintering process was carried out at 600°C under nitrogen atmosphere, and its consequence was the appearance of aluminium nitrides in composite microstructure acting as an additional strengthening phase. The composites were next re-pressed and re-sintered (2p2s) under the same conditions. The main aim of this article was to examine the microstructure of the SiC reinforced Al and Al4Cu alloy matrix composites. To achieve this goal and characterize the sintered materials, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used.

Open access

B. Dybowski, T. Rzychoń, B. Chmiela and A. Gryc

It is well known that the properties of a metal matrix composites depend upon the properties of the reinforcement phase, of the matrix and of the interface. A strong interface bonding without any degradation of the reinforcing phase is one of the prime objectives in the development of the metal matrix composites. Therefore, the objective of this work is to characterize the interface structure of WE43/SiC particles composite. Magnesium alloys containing yttrium and neodymium are known to have high specific strength, good creep and corrosion resistance up to 250°C. The addition of SiC ceramic particles strengthens the metal matrix composite resulting in better wear and creep resistance while maintaining good machinability. In the present study, WE43 magnesium matrix composite reinforced with SiC particulates was fabricated by stir casting. The SiC particles with 15 μm, 45 μm and 250 μm diameter were added to the WE43 alloy. The microstructure of the composite was investigated by optical microscopy, scanning electron microscopy, scanning transmission electron microscopy and XRD analysis. YSi and Y2Si reaction products are observed at the interfaces between SiC particles and WE43 matrix in the composite stirred at 780°C. Microstructure characterization of WE43 MMC with the 45 μm, stirred at 720°C showed relative uniform reinforcement distribution. Moreover, the Zr-rich particles at particle/matrix interface were visible instead of Y-Si phases. In the case of composite with 15 μm particles the numerous agglomerates and reaction products between SiC particles and alloying elements were observed. The presence of SiC particles assisted in improving hardness and decreasing the tensile strength and plastic properties.

Open access

K.-W. Kim, K.-S. Oh, H. Lee, B.-S. Kim and T.-J. Chung

Abstract

Two-step sintering route was applied for the densification SiC by promoting the role of liquid phase. The specimen contained 8 vol% of liquid phase composed of Al2O3 and Y2O3. The heating schedule consisted with initial rapid heating to 2000°C and immediate quenching to 1700 or 1750°C. By heating at elevated temperature, even distribution of the liquid phase was intended. The heat treatment at reduced temperature was to suppress the evaporative loss of the liquid and to secure the time for densification. The two-step sintering effectively suppressed loss of mass and coarsening. The resultant SiC was thus dense and was composed of fine grains exhibiting hardness of 2321 kgf/mm2.

Open access

M. Suśniak, P. Pałka and J. Karwan-Baczewska

Abstract

AlSi5Cu2/SiC nanocrystalline composite powder was successfully obtained by mechanical alloying of AlSi5Cu2 chips with reinforcement of 0, 10, 15, 20 wt. % of silicon carbide. X-ray powder diffraction was used to characterize obtained material. Detailed analyses using transmission and scanning electron microscopy have been conducted in order to collaborate the grain size measurement determined from the XRD analyses. Powders produced in a planetary ball mill with milling time: 1, 5, 10, 15, 20 and 40 hours, have shown shape and size evaluation during mechanical alloying process. It can be seen tendency to decrease the size of the grain as the milling time is increased. It is also noted that the grains of composites (AlSi5Cu2/SiC) are smaller than samples prepares without SiC addition. 40 hours of milling lead to formed very small grains of Al phase (20 nm in average) in composite powder.

Open access

Erika CsehovAaA, Jana AndrejovskAaA, Apichart Limpichaipanit, Ján Dusza and Richard Todd

Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites

The indentation load-size effect (ISE) in Vickers hardness of Al2O3 and Al2O3 + SiC nanocomposites has been investigated and analysed using Meyer law, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The strongest ISE was found for alumina. Both the PSR and MPSR models described the ISE well, but the MPSR model resulted in slightly lower true hardness values for all materials investigated. No evidence of the effect of machining stresses on the ISE has been found.

Open access

I. Dobosz, E. Rudnik and L. Burzyńska

, Thin Solid Films 95 , 133-142 (1982). S.W. Watson, Electrochemical study of SiC particle occlusion during nickel electrodeposition, J. Electrochem. Soc. 140 (8), 2235-2238 (1993). K.M. Ibrahim, A.A. Aal, Z.A. Hamid, Enhanced wear resistance of cast ductile iron by Ni-SiC composite coating, Int. J. Cast Met. Res. 18 (5), 318-320 (2005). E.A. Pavlatou, M. Stroumbouli, P. Gyftu, N. Spyrellis, Hardening effect induced by incorporation of SiC particles in nickel electrodeposits, J. Appl

Open access

Nisha Kondrath and Marian Kazimierczuk

References A. M. Abou-Alfotouh, A. V. Radun, H.-R. Chang, and C. Winterhalter, "A 1 MHz hard switched silicon carbide DC/DC converter," IEEE Transactions on Power Electronics , vol. 21, no. 4, pp. 880-889, July 2006. M. Bhatnagar and B. J. Baliga, "Comparison of 6H-SiC, 3C-SiC, and Si for power devices," IEEE Transactions on Electronic Devices , vol. 40, no. 3, p. 645, Mar. 1993. C. H. Carter, Jr., L. Tang, and R. F. Davis, "Growth of single crystal boules of 6H-SiC," in 4th

Open access

G. Chikvaidze, N. Mironova-Ulmane, A. Plaude and O. Sergeev

References 1. Pensl, G., & Choyke, W.J. (1993). Electrical and optical characterization of SiC. Physica B, 185, 264-283. 2. Cheung, R. (2006). Silicon Carbide Microelectromechanical Systems for Harsh Environments. Imperial College Press, Сh. 3, ISBN 1860946240. 3. Shenghuang Lin, Zhiming Chen, Lianbi Li, Yintu Ba, Sujuan Liu, & Mingchao Yang (2012). Investigation of micropipes in 6 H-SiC by Raman scattering. Physica, B40, 670-673. 4. Nakashima, S., & Harima, H. (1997). Raman investigation of SiC

Open access

W. Janke, A. Hapka and M. Oleksy

T. Oomori, "Some key researches on SiC device technologies and their predicted advantages", Power Semiconductors 6, 18-229 (2009). T. Funaki, J.C. Balda, J. Junghans, A.S. Kashyap, H.A. Mantooth, F. Barlow, T. Kimoto, and T. Hikihara, "Power conversion with SiC devices at extremely high ambient temperatures", IEEE Trans. on Power Electronics 22 (4), 1321-1329 (2007). http://www.cree.com/products/powerdocs2.asp http://www.sensitron.com/datasheets/5015.pdf K