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Advances in Materials Science and Engineering
Volume 2016, Article ID 9789061, 7 pages
http://dx.doi.org/10.1155/2016/9789061
Research Article

Electromagnetic Stirring versus ECAP: Morphological Comparison of Al-Si-Cu Alloys to Make the Microstructural Refinement for Use in SSM Processing

Materials and Manufacturing Engineering Department (MMED), Faculty of Mechanical Engineering (FEM), University of Campinas (UNICAMP), 13083-860 Campinas, SP, Brazil

Received 17 July 2016; Revised 17 August 2016; Accepted 20 September 2016

Academic Editor: Pavel Lejcek

Copyright © 2016 Luis Vanderlei Torres et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This work evaluates the morphological evolution at the semisolid state of the Al-4.0wt%Si-2.5wt%Cu alloy produced by direct chill casting under electromagnetic stirring (EMS) and by one equal channel angular pressing (ECAP) pass. The ECAP emerged as a promising technique capable of reduction and homogeneous metals microstructure imposing large deformations occurs in a matrix that contains two channels of the same cross-sectional area and forms an angle of 120°. The materials were submitted to reheating treatment in condition of 60% solid fraction at treatment times of 0, 30, and 90 s. Comparing the two cases, we have the presented ECAP process that had an excellent response to the recovery and recrystallization mechanisms, and refined microstructures ideal for thixoforming were produced. Primary particle sizes of about 45 μm and grain sizes of about 75 μm and a circularity shape factor of more than 0.60 were obtained. The low silicon alloy, Al-4.0wt%Si-2.5wt%Cu, presented excellent refinement when processed via equal channel angular pressing, presenting good morphological stability at the semisolid state, without significant changes in size or shape of the solid particles. This fully globular structure is favourable for thixoforming processes.