Study of the Influence of Silicon Phase Morphology on the Microstructural Stress Distribution in Al–Si Alloys Using Object Oriented Finite Element Modeling

Abstract

Near‐eutectic Al–Si alloys were produced by conventional casting and spray forming resulting in microstructural differences due to process dependent cooling rates. The as‐sprayed alloy exhibited fine equiaxed Si particles uniformly distributed throughout the matrix in contrast to the as‐cast alloy, which exhibited acicular morphology with relatively large needle‐like Si particles. The effect of Si morphology on the microstructural stress distribution of the as‐cast and as‐sprayed alloys was estimated by simulating uni‐axial tensile loads on microstructures using Object Oriented Finite Element code (OOF2). Microstructures of the as‐sprayed alloy experienced relatively low and uniform stress distribution, while the microstructural stress distribution in the as‐cast alloy was significantly influenced by the orientation of the needle shaped silicon particles.

Effect of scandium addition on the microstructure, mechanical and wear properties of the spray formed hypereutectic aluminum–silicon alloys

“…The various phases in the microstructure are identified by image analysis and appropriate material properties (Young's modulus and Poisson's ratio) are assigned to each of the phases followed by creating the mesh and applying the boundary conditions. In the present study, hypothetical microstructures representing the real microstructures of Al-Si alloys of various silicon particle sizes and shape were used and subjected to uni-axial tensile loading conditions using the procedure as explained by Raghukiran et al [14].…”

“…But all the spray deposits in the present study have shown similar wear resistance at the lower normal loads while alloys with higher silicon content have shown better wear performance at relatively higher normal pressures. It was reported that at relatively lower normal pressures, there was no much influence of the amount of silicon in the alloy [14]. This was attributed to the formation of oxide layer due to the built up of temperature that is relatively stable under smaller loads.…”

“…It is important to refine the eutectic and primary Si-phase that prevails in the size range of 100 mm or more in conventionally cast Al-Si hypereutectic alloys since it will lead to uniform distribution of stresses within the material improving mechanical performance of these alloys [14]. For instance, the effect of aspect ratio (AR) and size of the eutectic and primary silicon phases respectively on the microstructural stress distribution as predicted by the finite element modeling using OOF2 tool is presented in Fig.…”