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

Title: Microplastic flow in SIC/AL composites

Abstract

Experimentally it has been determined that if a composite containing a reinforcement which has a different (in general lower) thermal coefficient of expansion as compared to the matrix, then upon cooling from the processing or annealing temperature, plastic relaxation of the misfit strain will occur. Also, experimentally it has been shown that as the size of the reinforcement is increased, i.e., from small spheres to large spheres, there is a decrease in the summation of the effective plastic strain in the matrix. In other words there is a decrease in the average dislocation density in the matrix. However, if the shape of the reinforcement is changed from spherical to short fiber to continuous filament, then the dislocation density increases. This experimental data is obtained at a constant volume fraction. A very simple model of plastic relaxation based on prismatic punching of dislocations from the interface can account for the decrease in the dislocation density with an increase reinforcement size, and the increase in dislocation density when changing the shape from a sphere to a continuous filament. A FEM analysis of the shape factor is also capable of predicting the correct trend. However, at present the continuum mechanics methods that havemore » been investigated can not predict the size dependence. A simple model to explain the size effect in Al{sub 2}O{sub 3}/NiAl composites based on the deformation characteristics of NiAl will be discussed.« less

Authors:
 [1];  [2]
  1. Los Alamos National Lab., NM (United States)
  2. Univ. of Maryland, College Park, MD (United States)
Publication Date:
OSTI Identifier:
175317
Report Number(s):
CONF-950686-
TRN: 95:006111-0274
Resource Type:
Conference
Resource Relation:
Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; NICKEL ALLOYS; DEFORMATION; RELAXATION; ALUMINIUM ALLOYS; ALUMINIUM OXIDES; SILICON CARBIDES; ANNEALING; DISLOCATIONS; PROCESSING; INTERMETALLIC COMPOUNDS; PLASTICITY

Citation Formats

Shi, N., and Arsenault, R.J.. Microplastic flow in SIC/AL composites. United States: N. p., 1995. Web.
Shi, N., & Arsenault, R.J.. Microplastic flow in SIC/AL composites. United States.
Shi, N., and Arsenault, R.J.. Sun . "Microplastic flow in SIC/AL composites". United States.
@article{osti_175317,
title = {Microplastic flow in SIC/AL composites},
author = {Shi, N. and Arsenault, R.J.},
abstractNote = {Experimentally it has been determined that if a composite containing a reinforcement which has a different (in general lower) thermal coefficient of expansion as compared to the matrix, then upon cooling from the processing or annealing temperature, plastic relaxation of the misfit strain will occur. Also, experimentally it has been shown that as the size of the reinforcement is increased, i.e., from small spheres to large spheres, there is a decrease in the summation of the effective plastic strain in the matrix. In other words there is a decrease in the average dislocation density in the matrix. However, if the shape of the reinforcement is changed from spherical to short fiber to continuous filament, then the dislocation density increases. This experimental data is obtained at a constant volume fraction. A very simple model of plastic relaxation based on prismatic punching of dislocations from the interface can account for the decrease in the dislocation density with an increase reinforcement size, and the increase in dislocation density when changing the shape from a sphere to a continuous filament. A FEM analysis of the shape factor is also capable of predicting the correct trend. However, at present the continuum mechanics methods that have been investigated can not predict the size dependence. A simple model to explain the size effect in Al{sub 2}O{sub 3}/NiAl composites based on the deformation characteristics of NiAl will be discussed.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {12}
}

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: