Structural stability at elevated temperatures of the AlSi6Cu4 matrix composite with graphite particles
Journal Title: Archiwum Odlewnictwa - Year 2009, Vol 9, Issue 2
Abstract
The results of investigation of structure stability of the AlSi6Cu4 matrix alloy and composites with graphite particles at elevated temperatures were presented. Composites and matrix alloy were prepared by squeeze casting method and then they were annealed at 573 K and 673 K during 1, 20, 100, 500, and 1000 hours. The structures of composites and matrix alloy were observed and compared after annealing. Changes in the structure both in matrix alloy and composite were stated at both temperatures. These changes are characterised by the change in morphology of eutectic silicon, which needle-like grains turn into spheroids. The spheroidization starts in the pure alloy after 500 hours of annealing at 573 K and after 300 hours of annealing at 673 K. The changes occur sooner in the composite than in matrix alloy: they can be stated after 100 hours of annealing at 573 K, while at 673 K they started between 50 and 100 hours. The change in the morphology of eutectic silicon takes place faster along and among the graphite particles than in particle-free regions of composite. The matrix/graphite interface was found to be free of reaction products (Al4C3 and others).
Authors and Affiliations
Z. Komopka, M. Łągiewka, A. Zyska
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