skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The effect of particulate fracture in determining fracture toughness of metal matrix composites

Abstract

Although the fracture toughness of discontinuous reinforced metal matrix composites (DR MMCs) is reduced significantly in comparison to its matrix alloy, the fracture mode remains ductile for all Al- based materials studied. Failure of DR MMCs occurs ultimately by void growth and coalescence in the matrix phase, similar to unreinforced material. Brittle fracture of the particulates also contributes to the microfracture process and thus to fracture toughness. Fracture surface, metallographic, and acoustic emission results indicate that particulates contained in the process zone fracture either by single-faceted or multi-faceted cracking ahead of the main crack. Moreover, fracture of primary void initiating particulates depends on the reinforcement type, size, and the particulate/matrix interface microstructure. These factors influence the stress level at which void nucleation occurs at particulates. Fractographic evidence indicates that void nucleation and growth begin at a low nominal level of stress in particular for large particulates exhibiting extensive interfacial precipitation. Fracture of reinforcing particulates encompassed in the crack tip process zone has a strong effect on the fracture toughness of MMCs. Emphasis is placed on the role of particulate cracking and the mechanism of interparticulate ligament failure in determining the fracture toughness. In addition, fracture toughness results obtained by shortmore » bar and conventional compact tension methods were found to be in remarkable agreement. Using a stress-modified strain criterion continuum model for ductile fracture, the fracture toughness of particulate reinforced metal matrix composites is described reasonably well.« less

Authors:
 [1];  [2];  [3];  [4]
  1. Sandia National Labs., Livermore, CA (United States)
  2. Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center
  3. Sandia National Labs., Albuquerque, NM (United States)
  4. Army Materials Research Agency, Watertown, MA (United States). Materials Technology Lab.
Publication Date:
Research Org.:
Sandia National Labs., Livermore, CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10119387
Report Number(s):
SAND-90-8490; CONF-901008-13
ON: DE92006866
DOE Contract Number:  
AC04-76DR00789
Resource Type:
Conference
Resource Relation:
Conference: Fall meeting of the Minerals, Metals and Materials Society (TMS),Detroit, MI (United States),7-11 Oct 1990; Other Information: PBD: [1990]
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPOSITE MATERIALS; FRACTURE PROPERTIES; CRACK PROPAGATION; WHISKERS; REINFORCED MATERIALS; PARTICLE SIZE; MORPHOLOGY; TENSILE PROPERTIES; HEAT TREATMENTS; SILICON CARBIDES; MICROSTRUCTURE; ALUMINIUM BASE ALLOYS; SILICON ALLOYS; COPPER ALLOYS; 360603; 360602; MECHANICAL PROPERTIES; STRUCTURE AND PHASE STUDIES

Citation Formats

Lucas, J P, Liaw, P K, Stephens, J J, and Nunes, J. The effect of particulate fracture in determining fracture toughness of metal matrix composites. United States: N. p., 1990. Web.
Lucas, J P, Liaw, P K, Stephens, J J, & Nunes, J. The effect of particulate fracture in determining fracture toughness of metal matrix composites. United States.
Lucas, J P, Liaw, P K, Stephens, J J, and Nunes, J. 1990. "The effect of particulate fracture in determining fracture toughness of metal matrix composites". United States.
@article{osti_10119387,
title = {The effect of particulate fracture in determining fracture toughness of metal matrix composites},
author = {Lucas, J P and Liaw, P K and Stephens, J J and Nunes, J},
abstractNote = {Although the fracture toughness of discontinuous reinforced metal matrix composites (DR MMCs) is reduced significantly in comparison to its matrix alloy, the fracture mode remains ductile for all Al- based materials studied. Failure of DR MMCs occurs ultimately by void growth and coalescence in the matrix phase, similar to unreinforced material. Brittle fracture of the particulates also contributes to the microfracture process and thus to fracture toughness. Fracture surface, metallographic, and acoustic emission results indicate that particulates contained in the process zone fracture either by single-faceted or multi-faceted cracking ahead of the main crack. Moreover, fracture of primary void initiating particulates depends on the reinforcement type, size, and the particulate/matrix interface microstructure. These factors influence the stress level at which void nucleation occurs at particulates. Fractographic evidence indicates that void nucleation and growth begin at a low nominal level of stress in particular for large particulates exhibiting extensive interfacial precipitation. Fracture of reinforcing particulates encompassed in the crack tip process zone has a strong effect on the fracture toughness of MMCs. Emphasis is placed on the role of particulate cracking and the mechanism of interparticulate ligament failure in determining the fracture toughness. In addition, fracture toughness results obtained by short bar and conventional compact tension methods were found to be in remarkable agreement. Using a stress-modified strain criterion continuum model for ductile fracture, the fracture toughness of particulate reinforced metal matrix composites is described reasonably well.},
doi = {},
url = {https://www.osti.gov/biblio/10119387}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Dec 31 00:00:00 EST 1990},
month = {Mon Dec 31 00:00:00 EST 1990}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: