Study on in situ Al-Si functionally graded materials produced by traveling magnetic field

2012 ◽  
Vol 19 (3) ◽  
pp. 209-214 ◽  
Author(s):  
Yanjin Xu ◽  
Yanqing Su ◽  
Liangshun Luo ◽  
Jiangping Liu ◽  
Jingjie Guo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Wear Resistance ◽  
Functionally Graded Materials ◽  
Volume Fraction ◽  
Functionally Graded ◽  
Microstructural Feature ◽  
Graded Materials ◽  
Primary Si ◽  
Traveling Magnetic Field

AbstractThe aim of this contribution was to investigate the microstructure of in situ Al-Si functionally graded materials produced by traveling magnetic field. The research shows that the composition and associated microstructural feature of Al-Si alloys processed by this method changes from the outer of samples to the inner, respectively, from Al-Si hypereutectic with particles of primary Si to Al-Si eutectic to hypoeutectic composition with a great number of primary Al dendrites. Moreover, the hardness, the wear resistance of samples and the volume fraction of primary Si particles all have obviously gradient characteristics in the samples.

Solidification Processing of Functionally Graded Materials by Sedimentation

1999 ◽  
Author(s):  
J. W. Gao ◽  
S. J. White ◽  
C. Y. Wang
Keyword(s):  
Functionally Graded Materials ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Computer Code ◽  
Functionally Graded ◽  
Particle Volume ◽  
Particle Sedimentation ◽  
Graded Materials ◽  
Free Zone ◽  
Free Region

Abstract A combined experimental and numerical investigation of the solidification process during gravity casting of functionally graded materials (FGMs) is conducted. Focus is placed on the interplay between the freezing front propagation and particle sedimentation. Experiments were performed in a rectangular ingot using pure substances as the matrix and glass beads as the particle phase. The time evolutions of local particle volume fractions were measured by bifurcated fiber optical probes working in the reflection mode. The effects of various processing parameters were explored. It is found that there exists a particle-free zone in the top portion of the solidified ingot, followed by a graded particle distribution region towards the bottom. Higher superheat results in slower solidification and hence a thicker particle-free zone and a higher particle concentration near the bottom. The higher initial particle volume fraction leads to a thinner particle-free region. Lower cooling temperatures suppress particle settling. A one-dimensional solidification model was also developed, and the model equations were solved numerically using a fixed-grid, finite-volume method. The model was then validated against the experimental results, and the validated computer code was used as a tool for efficient computational prototyping of an Al/SiC FGM.

In situ multi-layer functionally graded materials by Electromagnetic Separation method

2005 ◽  
Vol 393 (1-2) ◽  
pp. 164-169 ◽  
Author(s):  
Changjiang Song ◽  
Zhenming Xu ◽  
Xiangyang Liu ◽  
Gaofei Liang ◽  
Jianguo Li
Keyword(s):  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Separation Method ◽  
Graded Materials ◽  
Electromagnetic Separation

Al2O3-Fe Functionally Graded Materials Fabricated under Magnetic Field

2005 ◽  
pp. 143-146
Author(s):  
A. Oziębło ◽  
K. Konopka ◽  
E. Bobryk ◽  
Mikolaj Szafran ◽  
Krzysztof J. Kurzydłowski
Keyword(s):  
Magnetic Field ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Graded Materials

Effects of Particle Size on Fabrication of Al-TiO2 Functionally Graded Materials by Centrifugal Mixed-Powder Method

2016 ◽  
Vol 879 ◽  
pp. 1691-1697 ◽  
Author(s):  
Hisashi Sato ◽  
Junya Maeda ◽  
Motoko Yamada ◽  
Yoshimi Watanabe
Keyword(s):  
Particle Size ◽  
Wear Resistance ◽  
Functionally Graded Materials ◽  
Casting Process ◽  
Functionally Graded ◽  
The Other ◽  
Mixed Powder ◽  
Graded Materials ◽  
Powder Method ◽  
Al Matrix

As one of processing methods of functionally graded materials (FGMs), centrifugal mixed-powder method has been proposed. The centrifugal mixed-powder method is the casting process combined of centrifugal casting and powder metallurgy. This processing method has advantage that fine ceramics-particles, whose wettability with matrix melt is low, can be compounded into metallic material. However, effects of particle size on microstructure and mechanical properties of the FGMs fabricated by the centrifugal mixed-powder method are unclear. In this study, two kinds of Al-TiO2 FGMs rings are fabricated by the centrifugal mixed-powder method. One contains TiO2 particles having similar diameter with Al matrix particles (hereafter, small different-size (SD) TiO2 particles), and the other one compounds TiO2 particles with much smaller diameter than Al matrix particles (hereafter, large different-size (LD) TiO2 particles). In case of the Al-TiO2 FGMs ring containing SD-TiO2 particles, the TiO2 particles are homogeneously dispersed in Al matrix on outer surface of the ring. On the other hand, the TiO2 particles in the Al-TiO2 FGMs ring with LD-TiO2 particles are distributed along grain boundary of Al matrix. Moreover, Vickers-hardness and wear resistance around outer surface of the Al-TiO2 FGMs ring containing the SD-TiO2 particles is higher than that of the Al-TiO2 FGMs ring with LD-TiO2 particles. Since Al particles in the mixed-powder with LD-TiO2 particles are surrounded by the TiO2 particles, the Al particles can be hardly melted by heat of molten Al at casting process. As a result, the Al-TiO2 FGMs ring with LD-TiO2 particles has low hardness and wear resistance. Therefore, it is found that TiO2 particles having similar diameter with Al matrix particles are more suitable for fabrication of the Al-TiO2 FGMs rings.

Designing Optimal Volume Fractions For Functionally Graded Materials With Temperature-Dependent Material Properties

2006 ◽  
Vol 74 (5) ◽  
pp. 861-874 ◽  
Author(s):  
Florin Bobaru
Keyword(s):  
Functionally Graded Materials ◽  
Material Properties ◽  
Volume Fraction ◽  
Effective Properties ◽  
Functionally Graded ◽  
Dominant Factor ◽  
Temperature Dependent ◽  
Graded Materials ◽  
Critical Stresses ◽  
Non Linear

We present a numerical approach for material optimization of metal-ceramic functionally graded materials (FGMs) with temperature-dependent material properties. We solve the non-linear heterogeneous thermoelasticity equations in 2D under plane strain conditions and consider examples in which the material composition varies along the radial direction of a hollow cylinder under thermomechanical loading. A space of shape-preserving splines is used to search for the optimal volume fraction function which minimizes stresses or minimizes mass under stress constraints. The control points (design variables) that define the volume fraction spline function are independent of the grid used in the numerical solution of the thermoelastic problem. We introduce new temperature-dependent objective functions and constraints. The rule of mixture and the modified Mori-Tanaka with the fuzzy inference scheme are used to compute effective properties for the material mixtures. The different micromechanics models lead to optimal solutions that are similar qualitatively. To compute the temperature-dependent critical stresses for the mixture, we use, for lack of experimental data, the rule-of-mixture. When a scalar stress measure is minimized, we obtain optimal volume fraction functions that feature multiple graded regions alternating with non-graded layers, or even non-monotonic profiles. The dominant factor for the existence of such local minimizers is the non-linear dependence of the critical stresses of the ceramic component on temperature. These results show that, in certain cases, using power-law type functions to represent the material gradation in FGMs is too restrictive.

A novel magnetic-field-driving method for fabricating Ni/epoxy resin functionally graded materials

2018 ◽  
Vol 222 ◽  
pp. 70-73 ◽  
Author(s):  
Jing Li ◽  
Xiaoling Peng ◽  
Yanting Yang ◽  
Jiangcai Xu ◽  
Panfeng Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Epoxy Resin ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Graded Materials

On the mechanical properties of functionally graded materials reinforced by carbon nanotubes

2017 ◽  
Vol 232 (9) ◽  
pp. 1632-1646 ◽  
Author(s):  
Saeed Rouhi ◽  
Seyed H Alavi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Functionally Graded Materials ◽  
Volume Fraction ◽  
Single Walled Carbon Nanotubes ◽  
Functionally Graded ◽  
Graded Materials ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

In this paper, the elastic properties of functionally graded materials reinforced by single-walled carbon nanotubes are studied. Three different matrices, including steel-silicon, iron-alumina and alumina-zirconia are considered. Besides, the effects of nanotube length, radius and volume fraction on the Young’s modulus of functionally graded matrices reinforced by single-walled carbon nanotubes are investigated. It is observed that short nanotubes not only cannot increase the longitudinal elastic modulus of the matrices, but sometimes decrease their elastic modulus. Of the three selected matrices, steel-silicon matrix would have the most enhancement. Investigation of the effect of nanotube volume fraction on the mechanical properties of nanocomposites shows that increasing the volume fraction of long single-walled carbon nanotube results in increasing the elastic modulus of the nanocomposites.

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