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

Title: Measurements of the Bauschinger effect in some particulate Al[sub 2]O[sub 3]/Al and SiC/Al metal matrix composites

Journal Article · · Scripta Metallurgica et Materialia; (United States)
 [1];  [2]
  1. Materials Research Lab., DSTO, Ascot Vale, Victoria (Australia)
  2. Univ. of New South Wales, Kensington (Australia)

The Bauschinger effect in SiC/Al composites has been attributed to a number of possible mechanisms. Numerous studies have suggested that relatively high residual tensile stresses in the aluminum matrix are the principal cause of the Bauschinger effect. These stresses are produced by the large difference in the coefficients of thermal expansion between the SiC and Al phases. Arsenault and Taya measured stresses as high as 408 MPa in the aluminium phase of a SiC whisker (5% volume fraction)/6061 Al composite using x-ray diffraction techniques, while Withers et al. measured strains of about 7 [times] 10[sup [minus]4] in a similar composite using neutron diffraction. Due to the presence of tensile stresses in the matrix, Arsenault et al. and Taya et al. suggest that the Bauschinger effect arises because the flow stress of the composite is reduced when pre-straining is performed in tension and is raised when performed in compression. They also believe that other mechanisms such as differences in the dislocation configurations that may form as a result of pre-straining in tension or compression are not likely to contribute significantly to the Bauschinger effect. However, Withers et al. and Warner et al. suggest that relaxation processes such as diffusion and plastic flow in the aluminium matrix may contribute to the Bauschinger effect. This paper describes the results of a preliminary study of the Bauschinger effect in particulate Al[sub 2]O[sub 3]/Al composites, and compares their behavior to some SiC/Al composites.

OSTI ID:
6444948
Journal Information:
Scripta Metallurgica et Materialia; (United States), Vol. 28:11; ISSN 0956-716X
Country of Publication:
United States
Language:
English