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

Title: Toughening mechanisms in Al/Al-SiC laminated metal composites

Abstract

The fracture toughness of laminated metal composites consisting of alternating layers of a metal matrix composite (Al6090/SiC/25p) and a monolithic aluminum alloy (Al5182) has been studied as a function of the volume fraction of the component materials. Finite element simulations of the fracture toughness tests have been used to study the mechanisms of crack growth and extrinsic toughening. The mechanisms responsible for toughening in laminated metal composites are described.

Authors:
; ; ;  [1];  [2];  [3]
  1. Lawrence Livermore National Lab., CA (United States)
  2. Case Western Reserve Univ., Cleveland, OH (United States)
  3. Alcoa Technical Center, Alcoa Center, PA (United States)
Publication Date:
OSTI Identifier:
490776
Report Number(s):
CONF-960401-
ISBN 1-55899-337-1; TRN: IM9729%%27
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Book
Resource Relation:
Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 8-12 Apr 1996; Other Information: PBD: 1996; Related Information: Is Part Of Layered materials for structural applications; Lewandowski, J.J. [ed.] [Case Western Reserve Univ., Cleveland, OH (United States)]; Ward, C.H. [ed.] [Air Force Office of Scientific Research, Bolling AFB, DC (United States)]; Jackson, M.R. [ed.] [General Electric Corporate R and D, Schenectady, NY (United States)]; Hunt, W.H. Jr. [ed.] [Alcoa Technical Center, Alcoa Center, PA (United States)]; PB: 325 p.; Materials Research Society symposium proceedings, Volume 434
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; FRACTURE PROPERTIES; ALUMINIUM BASE ALLOYS; SILICON CARBIDES; COMPOSITE MATERIALS; LAYERS; CONCENTRATION RATIO; SIMULATION; FINITE ELEMENT METHOD; CRACK PROPAGATION; INTERFACES; EXPERIMENTAL DATA

Citation Formats

Lesuer, D.R., Wadsworth, J., Riddle, R.A., Syn, C.K., Lewandowski, J.J., and Hunt, W.H. Jr. Toughening mechanisms in Al/Al-SiC laminated metal composites. United States: N. p., 1996. Web.
Lesuer, D.R., Wadsworth, J., Riddle, R.A., Syn, C.K., Lewandowski, J.J., & Hunt, W.H. Jr. Toughening mechanisms in Al/Al-SiC laminated metal composites. United States.
Lesuer, D.R., Wadsworth, J., Riddle, R.A., Syn, C.K., Lewandowski, J.J., and Hunt, W.H. Jr. Tue . "Toughening mechanisms in Al/Al-SiC laminated metal composites". United States. doi:.
@article{osti_490776,
title = {Toughening mechanisms in Al/Al-SiC laminated metal composites},
author = {Lesuer, D.R. and Wadsworth, J. and Riddle, R.A. and Syn, C.K. and Lewandowski, J.J. and Hunt, W.H. Jr.},
abstractNote = {The fracture toughness of laminated metal composites consisting of alternating layers of a metal matrix composite (Al6090/SiC/25p) and a monolithic aluminum alloy (Al5182) has been studied as a function of the volume fraction of the component materials. Finite element simulations of the fracture toughness tests have been used to study the mechanisms of crack growth and extrinsic toughening. The mechanisms responsible for toughening in laminated metal composites are described.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}

Book:
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 book.

Save / Share:
  • Previous studies revealed that damping capacity of Al alloys can be improved through particle reinforced metal matrix composite (MMC) processing. Addition of graphite particles may produce a substantial increase in damping capacity but introduce a decrease in modulus. Addition of SiC particles, however, improves modulus while maintaining a comparable or slightly superior damping capacity to that of matrix alloys. Considering the very different effects of graphite and SiC particles on the properties of Al alloys, SiC and graphite particle hybrid reinforced 6061 Al MMCs (6061Al/SiC/Gr) were fabricated using a spray deposition technique in an effort to develop a high dampingmore » and high modulus material. Two ratios of SiC to graphite particle volumes were used to explore optimal combination of damping and modulus of the hybrid MMCS. Both damping capacity and storage modulus were evaluated on a dynamic mechanical thermal analyzer. Experimental results showed that the 6061Al/SiC/Gr hybrid MMCs exhibited a higher damping than the 6061/SiC and a higher modulus than 6061/Gr MMCs with similar volume fraction of reinforcement. The operative damping mechanisms are discussed on the basis of microstructural analyses. The improvement in damping capacity of the hybrid MMCs is discussed in terms of microstructural modification in the matrix and generation of interfaces due to the presence of SiC and graphite particles.« less
  • A constitutive model for deformation of a novel laminated metal composite (LMC) which is comprised of 21 alternating layers of Al 5182 alloy and Al 6090/SiC/25p metal matrix composite (MMC) has been proposed. The LMC as well as the constituent or neat structures have been deformed in uniaxial tension within a broad range of strain-rates (i.e., 10{sup {minus}5} to 10{sup 0}s{sup {minus}1}) and homologous temperatures (i.e., 0.8 {ge} 0.95 T{sub m}). The results of these experiments have led to a thorough characterization of the mechanical behavior and a subsequent semiempirical constitutive rate equation for both the Al 5182 and Almore » 6090/SiC/25p when tested monolithically. These predictive relations have been coupled with a proposed model which takes into account the dynamic load sharing between the elastically stiffer and softer layers when loaded axially during isostrain deformation of the LMC. This model has led to the development of a constitutive relationship between flow stress and applied strain-rate for the laminated structure.« less
  • The growth rates and mechanisms of short fatigue cracks in Al-SiC composites have been studied in various researches. Few of these works, however, have used the same types of specimens and/or testing conditions. Nevertheless, comparisons between the results of the same or similar materials using different testing methods have been common. Little work has been performed to assess whether such comparisons are reliable. This study examines the growth of short fatigue cracks for both notched and smooth specimens of a 2xxx-type aluminum matrix reinforced with silicon carbide particulates to investigate whether the growth rates and mechanisms can be properly compared.more » Notched specimens are the primary sources of long crack and physically-short crack data. On the other hand, growth data involving microstructurally-short cracks, or microcracks, are followed from smooth specimens. The results of this study indicate that there can be significant differences in the growth rates of short cracks in notched and smooth specimens of Al-SiC composites with the former being up to 2 orders higher. The growth mechanisms of short cracks in the two types of specimens, however, appear to be quite similar.« less
  • Al 5182/Al 6061-25 vol.% SiCp and ultrahigh carbon (1.8% C) steel/brass (70% Cu-30% Zn type) laminates were prepared by press-bonding stacks of alternating layers of the component materials. Press bonding of these materials required consideration of the flow stresses of the component materials and the interlayer friction. Tensile properties and fracture toughness were measured for different processing conditions of surface oxide descaling, layer thickness, and heat treatment. Descaling of the surface oxide prior to the press-bonding was found to eliminate premature delamination along interfaces resulting in an increased yield strength and tensile ductility. Reduction in the layer thickness brought anmore » increase in the tensile ductility for both laminates, a decrease in yield strength and fracture toughness for the Al laminate. T6 heat treatment on the Al laminate induced a substantial increase in the yield and tensile strength but a decrease in tensile ductility. Fracture surface morphology indicated evidences of local delamination, crack blunting and bridging. Fracture toughness measured in the crack arrester and crack divider orientation showed a substantial enhancement over that of the Al 6061-SiCp or UHCS components.« less
  • We have fabricated laminated metal composites of (1) ultrahigh carbon steel (1.8%C) and brass (70Cu-30Zn), and (2) aluminum 5182 and aluminum 6061 with 25 vol.% SiCp. The laminates were prepared by hot pressing alternating layers of the component materials in an argon gas atmosphere. The steel was thermo-mechanically processed to produce a fine grained microstructure that exhibited superplasticity. The brass and aluminum materials were obtained from commercial sources and used in the as-received condition. Laminates with different numbers of layers and layer thickness were made. The compressive stress and strain rate were measured during hot pressing, and material flow behaviormore » in the UHCS-brass laminate was found to be rate-controlled by the stronger component rather than by the softer one (brass). Material flow behavior was more complicated in the Al-laminate. Tensile and fracture behavior were determined by tensile tests and by chevron notched fracture toughness tests. Details of processing, microstructure and initial results of mechanical property tests of these laminates are discussed.« less