On microstructural evolution and micromechanical modelling of deformation of a whisker-reinforced metal-matrix composite Academic Article uri icon

abstract

  • The precipitation characteristics, the mechanisms of accelerated aging, and the variation of uniaxial tensile stress-strain behavior in response to controlled variations in matrix microstructure were investigated for a 2124 AlSiC whisker composite. The yield strength of the composite was found to be independent of matrix aging condition. However, the overall ductility decreased monotonically with an increase in aging time. A finite element analysis of the constitutive response of the composite is presented. The results of these calculations, as well as the predictions of several models for composite strengthening available in the literature, were compared with the experimental results. The presence of brittle whiskers in aluminum leads to a significant build-up of hydrostatic stresses in the matrix during plastic deformation. Void formation in the matrix of the composite as well as at the whisker-matrix interface appears to play an important role in controlling the overall failure mechanisms. Transmission electron microscopy observations of void formation a whisker ends are described for composite specimens strained in tension at room temperature and at 300°C. A detailed discussion of matrix deformation and interfacial debonding is presented in an attempt to identify the origins of low ductility in discontinuously reinforced metal-ceramic composites. © 1989.

published proceedings

  • Materials Science and Engineering: A

author list (cited authors)

  • Christman, T., Needleman, A., Nutt, S., & Suresh, S

citation count

  • 216

complete list of authors

  • Christman, T||Needleman, A||Nutt, S||Suresh, S

publication date

  • January 1989