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Metal Matrix Composites: Discontinuously Reinforced, Microstructure and Mechanical Property Correlations

  1. Elisabetta Gariboldi

Published Online: 20 JUL 2012

DOI: 10.1002/9781118097298.weoc142

Wiley Encyclopedia of Composites

Wiley Encyclopedia of Composites

How to Cite

Gariboldi, E. 2012. Metal Matrix Composites: Discontinuously Reinforced, Microstructure and Mechanical Property Correlations. Wiley Encyclopedia of Composites. 1–16.

Author Information

  1. Politecnico di Milano, Milano, Italy

Publication History

  1. Published Online: 20 JUL 2012

Abstract

In discontinuously reinforced metal matrix composites, pure metal or alloy matrices are typically reinforced by means of particles, whiskers, and short fibers, although the use of other reinforcement geometries is possible. The microstructural features characterizing a discontinuously reinforced composite (DRC) have been grouped and discussed as matrix, reinforcement, or interface features in this article. The correlations between them and the mechanical properties of the composites have been addressed by dealing with specific materials and micromechanical models as examples. Among material properties, the focus is mainly on the mechanical ones. With the help of an example, it was shown that, since the elastic modulus of a DRC is mainly related to the elastic properties of the matrix and reinforcement as well as to the geometry, it can be relatively easily predicted and controlled during material fabrication and processing. On the other hand, the yield strength is additionally related to other microstructural features, for example, the matrix grain size, and it is thus severely affected and can be considerably improved by optimized DRC fabrication and processing steps, but it cannot be easily predicted without taking the process parameters into account. Lastly, a number of mechanical properties correlated to local or general rupture, such as UTS, fatigue properties, creep rupture times, are affected by the onset and evolution of microstructural damage, since damage alters load transfer conditions. Therefore, a part of the article focuses on mechanisms of microstructural damage and on the interesting models proposed in literature to link it to microstructural features.

Keywords:

  • discontinuously reinforced metal matrix composites;
  • elastic moduli;
  • tensile;
  • creep;
  • fatigue;
  • microstructural damage;
  • reinforcement properties