Evaluation of particle size and shape distributions in Al-Al<SUB align=right>3Ni Functionally Graded Materials fabricated by a semi-solid forming process

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.

Download Full-text

Fabrication of W–Cu functionally graded materials with high density by particle size adjustment and solid state hot press

Composites Science and Technology ◽

10.1016/j.compscitech.2007.10.023 ◽

2008 ◽

Vol 68 (6) ◽

pp. 1539-1547 ◽

Cited By ~ 31

Author(s):

Bin-Bin Liu ◽

Jian-Xin Xie ◽

Xuan-Hui Qu

Keyword(s):

Particle Size ◽

Solid State ◽

Functionally Graded Materials ◽

Functionally Graded ◽

High Density ◽

Hot Press ◽

Graded Materials ◽

Size Adjustment

Download Full-text

Plasma Processing of Functionally Graded Materials: Diagnostics and Characterization

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0317 ◽

1996 ◽

Author(s):

W. Smith ◽

T.J. Jewett ◽

S. Sampath ◽

C.C. Berndt ◽

H. Herman ◽

...

Keyword(s):

Particle Size ◽

Functionally Graded Materials ◽

Deposition Efficiency ◽

Functionally Graded ◽

Compositional Variation ◽

Continuous Change ◽

Particle Segregation ◽

Graded Materials ◽

Engineering Problems ◽

Interface Effects

Abstract Functionally graded materials (FGMs) offer solutions to such engineering problems involving multi-layer systems with large differences in CTE, i.e. thermal barrier coatings, by allowing for a continuous change in the properties over a defined distance, thus minimizing sharp interface effects. By its nature, plasma spraying is well suited to the fabrication of FGMs. However, in order to achieve optimal performance from the material it is necessary to ensure the FGM is uniform in its compositional variation. The deposition efficiency of the particulate species as well as their trajectories will determine the degree of homogeneity of the FGM. It is therefore important that the inter-relationships between the particle size distributions, injection orientation and feed rates are determined. Towards this end, a series of investigations have been carried out to determine the effects of injection orientation on the particle segregation. Analysis of the particle segregation as a function of particle size distribution was then examined in the formation of FGMs. The results indicate that optimal deposition occurs when the various particle species trajectories converge as they approach the substrate.

Download Full-text

A micropolar model for elastic properties in functionally graded materials

Advances in Mechanical Engineering ◽

10.1177/1687814018789520 ◽

2018 ◽

Vol 10 (8) ◽

pp. 168781401878952 ◽

Cited By ~ 1

Author(s):

Shengyao Fan ◽

Zhanqi Cheng

Keyword(s):

Particle Size ◽

Elastic Properties ◽

Functionally Graded Materials ◽

Effective Properties ◽

Matrix Material ◽

Functionally Graded ◽

Two Phase ◽

Graded Materials ◽

Micromechanics Model ◽

Matrix Zone

By considering the description of phase volume fractions, a micromechanics model is presented for predicting the elastic mechanical properties of isotropic two-phase functionally graded materials. The particle size dependence of the overall elasticity of functionally graded materials is not generally considered by classical continuum micromechanics; however, being based on micropolar theory, the presented micromechanics model is able to study such size effects. As the effective material properties vary gradually along the gradation direction, a functionally graded material can be divided into two distinct zones: the particle–matrix zone and the transition zone. In the particle–matrix zone, the matrix material is idealized as a micropolar continuum and Mori–Tanaka’s method is extended to the micropolar medium to evaluate the effective elastic properties. The effective properties across the gradation forms are further derived and the effects of particle size on the effective properties of a functionally graded materials are also studied. The validity and effectiveness of the present model is demonstrated by comparing the model results with other model outputs and experimental data.

Download Full-text