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In this paper, a generation-based optimization method is proposed to reconstruct three-dimensional (3D) finite element (FE) model of co-continuous SiC 3D /Al composites. Investigation of dynamic numerical simulation is applied to the model. Then an optimization design of different infill materials, volume fractions and distribution characters is proposed. After research among the three infill materials of Al, PU and epoxy, the SiC 3D /Al composites have the best dynamic behavior. Then different SiC 3D /Al composite models are reconstructed by changing the volume fraction and core distribution probability in the reconstruction method. The results indicate that the peak stress raise significantly along with the increasing of SiC volume fraction. But in the unloading stage, the composites appear a sustaining compressive capacity when the SiC volume fraction is lower. Remaining mass rate and failure contour are studied to research the failure process. The stress is also influenced by the distribution characters significantly. At last, the composites are optimized. [ABSTRACT FROM AUTHOR]

In this study, a 3D solid model of co-continuous ceramic composites was reconstructed using a single 2D microstructure section image. First, the volume fractions and distribution functions of both metallic alloy and ceramic phases were statistically obtained by analyzing a single 2D microstructure SEM image after binarization. The distribution functions of the two phases were then revised to generate a Gaussian random field. A 3D solid model of co-continuous ceramic composites was obtained through 3D fast Fourier transform. A Micro-CT model was proposed for comparison. Volume fraction and distribution function differences between the reconstructed model and the Micro-CT model were acceptable within the tolerance range. Results confirmed that the reproduced solid model retained the original geometrical characteristics of the real 2D microstructure SEM image as well as the micro-CT model. [ABSTRACT FROM AUTHOR]

It is difficult for co-continuous metal/ceramic composite with complex spatial topology to establish three-dimensional (3D) solid model. A generation-based optimization method is proposed to reconstruct 3D solid model. Firstly, pre-processing of the composite SEM image is applied to obtain two-dimensional (2D) digital matrix using a maximum between-cluster variance method, metallic and ceramic phases are segmented accurately. 2D generation core field is obtained following the principles proposed in the paper. Secondly, an optimization method is proposed and applied for the randomly distributed 3D cores to match the core distribution characteristics. Thirdly, a modified real-time changing directional growth probability is applied to form a smooth interface between the two phases. Finally, volume fractions and 2-point correlation functions of the reconstructed model and a micro-CT model are compared to verify the accuracy. This method can be used to reconstruct the 3D model of other materials with different microstructures such as titanium alloy. [ABSTRACT FROM AUTHOR]

Abstract: A high temperature Al(−)/glass/stainless steel–O2(+) system, was studied and characterized by SEM and EDS analysis. Indeed, a potential ranging from 1.75 to 1.5V between steel and aluminum, at a temperature above 500°C, has been observed. By connecting this package to a resistance, a current flow was detected. Above the aluminum melting point, there is a reaction between SiO2 glass and metal, with formation of Al2O3 and Si, moreover there is a change in the soda-lime glass composition, a nucleation of crystalline phases in the glass itself, and the formation of a porous layer of alumina, with the typical inhomogeneity of a system heated at this temperature. It seems that the current passing through the glass phase, by the electric field generated by the formation of a metal/air cell, can influence the composition of the glass phase at high temperature and can inhibit the nucleation and the growth of crystalline zones. [Copyright &y& Elsevier]

A novel approach of a gas pressure infiltration technique is presented for the synthesis of Co-Continuous Ceramic Composite (C4). SiC foams of varying pore sizes were infiltrated with aluminium AA5083. Optical examination revealed that the SiC foams contained open cells with a network of triangular voids. The number of pores-per-inch (PPI) in the foams was found to depend on the strut thickness and pore diameter. The compressive strengths of two foam configurations, 10 and 20 PPI, were estimated to lie between 1–2 MPa. After infiltration, the compressive yield strength of the resulting C4 was observed to increase to 126 MPa and 120 MPa, respectively, for the 10 and 20 PPI C4. Additionally, the infiltration of ceramic foam with the AA5083 alloy resulted in an increase in strength of 58–100 times when compared with plain ceramic foam. The failure modes of the composites in compression were analyzed by crack propagation and determining the type of failure. The study revealed that shear failure and vertical splitting were the predominant mechanisms of compression failure, and that the fabricated C4 is advantageous in mechanical properties compared to the plain ceramic foam. This study, therefore, suggests the use of C4 composites in armour applications. [ABSTRACT FROM AUTHOR]