Chapter 30. The Effects of Thermal Exposure on the Properties of Particulate SiC/Al Composites

  1. William J. Smothers
  1. Alison Skinner,
  2. Michael J. Koczak and
  3. Alan Lawley

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291092.ch30

Proceedings of the 5th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 2, Issue 7/8

Proceedings of the 5th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 2, Issue 7/8

How to Cite

Skinner, A., Koczak, M. J. and Lawley, A. (1981) The Effects of Thermal Exposure on the Properties of Particulate SiC/Al Composites, in Proceedings of the 5th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 2, Issue 7/8 (ed W. J. Smothers), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291092.ch30

Author Information

  1. Drexel University, Dept. of Materials Engineering Philadelphia, Pa. 19104

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1981

ISBN Information

Print ISBN: 9780470373903

Online ISBN: 9780470291092

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Keywords:

  • metallurgy;
  • microscopy;
  • microstructure;
  • aluminum;
  • isothermal

Summary

Aluminum matrix composites reinforced with SiC particulates (diameter < 10 μm) provide for a low-cost, high-modulus material that can be processed via conventional powder metallurgy techniques. With increased additions of SiC reinforcement, the modulus increases, and losses in strength, ductility, and toughness may occur. Also, the role of the interfacial bond between SiC particulates and the aluminum matrix may further detract from the mechanical properties when the composite is subjected to high temperatures. The role of thermal aging on mechanical properties and interface reactions of SiC-reinforced aluminum was thus investigated. Mechanical property and microstructure studies were conducted to evaluate the properties of particulate-SiC-reinforced 2024 aluminum produced by DWA. The 25 vol% particulate SiC composite in an aluminum (2024) matrix has ultimate strengths comparable to 2024; however, it exhibited lower yield strengths and durability. The ultimate strength of the SiC particulate material was apparently insensitive to thermal exposure at 500°C, e.g., UTS = 450 MPa for a thermal aging time of 72 h. Degradation in strength, e.g., UTS=290 MPa, was observed after 168-h exposure. Optical and scanning electron microscopy confirmed the insensitivity of the room-temperature properties and microstructures of the SiC particulate material to isothermal exposure at 500°C. Attention was also directed to the microstructure, and failure mode considerations, where initiation sites are associated with microvoid formation at SiC particles.