The role of particle cracking in dilatation during tensile straining of a cast and thermomechanically processed 6061 Al - 20 volume percent Al2O3 metal matrix composite
Boyle, Kevin P.
McNelley, Terry R.
MetadataShow full item record
In this work, the dilatation during tensile straining of a cast and thermomechanically processed 6061 Al - Al2O3 metal matrix composite (MMC) containing 20 volume percent of Al2O3 particles was examined. Standard tensile samples of the MMC and unreinforced 6061 Al were machined. Precise diameter measurements were made of both composite and unreinforced samples prior to and immediately following tensile straining. Tension tests were conducted to various strains as well as to fracture and an extensometer was employed to obtain accurate measurement of the axial strain. The MMC material exhibited a continuously increasing dilatation during tensile straining while the unreinforced 6061 control material deformed plastically at constant volume. Careful metallographic preparation revealed particle cracking in all MMC samples throughout the range of strains examined. A clear trend of increased frequency of particle cracking was observed. Void formation and growth due to cracking of the particles was analyzed and shown to correlate with the dilatation observed during tensile straining of the composite. Linkage of such voids is proposed as the mechanism of crack propagation at failure of the MMC.
Approved for public release; distribution is unlimited.
Showing items related by title, author, creator and subject.
Boey, Yew Khuan (Monterey, California. Naval Postgraduate School, 2011-12);This study investigated the progressive damage/failure of composite panels with open circular holes under progressive axial loading. A series of experiments was carried out to determine the failure in laminated specimens ...
Craugh, Linda E. (Monterey, California. Naval Postgraduate School, 1999-03-01);The objective of this study was to model and simulate progressive failure initiating from a notch tip in a laminated fibrous composite subjected to tensile in-plane loading. The micro/macro-level approach was used for this ...
Henry, Eugene M. (Monterey, California: U.S. Naval Postgraduate School, 1960);Heat-affected zone cracking in the welding of modified HY-80 steel (thicknesses greater than 1-1/4")has been a serious and costly problem in the nuclear submarine construction program. Welded joints fabricated with a ...