STP1360

    The Fracture and Fatigue Crack Growth Behavior of Forged Damage-Tolerant Niobium Aluminide Intermetallics

    Published: Jan 2000


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    Abstract

    The micromechanisms of fracture and fatigue crack growth are elucidated for a new class of damage-tolerant niobium aluminide Nb3Al-xTi intermetallics. Fatigue crack growth in alloys containing 10 and 25 at% Ti is shown to occur primarily by cleavage, while alloys containing ∼40 at% Ti are shown to exhibit similar fracture and fatigue crack growth behavior to ductile metals and their alloys. Slower elevated-temperature (750°C) crack growth rates in the Nb3Al-40Ti alloy are attributed largely to the effects of oxide-induced crack closure. The transition from cleavage fracture (in the Nb3Al-10Ti and Nb3Al-25Ti alloys) to ductile fracture in the Nb3Al-40Ti is correlated with the onset of significant levels of crack-tip plasticity, which is predicted using atomistic simulations.

    Keywords:

    fatigue, fracture, niobium aluminide, atomistic simulation, toughness


    Author Information:

    Ye, F
    Post-doctoral research associate, The Ohio State University, Columbus, OH

    Mercer, C
    Post-doctoral research associate, The Ohio State University, Columbus, OH

    Farkas, D
    Professor, Virginia Polytechnic Institute and State University, Blacksburg, VA

    Soboyejo, WO
    Professor, Princeton University, Princeton, NJ


    Paper ID: STP13409S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP13409S


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