STP890

    Effects of Alloy Chemistry on Superplastic Forming of Rapid-Solidification-Processed Aluminum-Lithium Alloys

    Published: Jan 1986


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    Abstract

    The superplastic forming characteristics of rapid-solidification-processed (RSP) Al-3Li-based alloys containing varying amounts of copper, magnesium, cobalt, and zirconium and processed by different thermomechanical sequences were investigated. Their final microstructures were strongly dependent on the processing treatment and alloy composition. All the zirconium-containing alloys were processed to have a fine subgrain microstructure. These alloys deform predominantly by dislocation glide and climb processes and by subgrain boundary motion, and they exhibit up to 400% elongation, which is sufficient for many commercial forming applications. Cavitation was suppressed, and the mechanical properties were not affected by forming. A thermomechanical processing sequence was established that develops a completely recrystallized fine grain microstructure in the Al-Li-Cu-Zr alloys. The alloys with this recrystallized microstructure have excellent formability.

    Keywords:

    powder metallurgy, superplastic forming, lithium, rapid solidifcation processing, aluminum alloys, microstructure refinement, low-density high-modulus aluminum PM alloys, Al-Li-Cu-Zr alloys


    Author Information:

    Lederich, RJ
    Scientist and senior scientists, McDonnell Douglas Research Laboratories, St. Louis, MO

    Meschter, PJ
    Scientist and senior scientists, McDonnell Douglas Research Laboratories, St. Louis, MO

    Sastry, SML
    Scientist and senior scientists, McDonnell Douglas Research Laboratories, St. Louis, MO


    Paper ID: STP33037S

    Committee/Subcommittee: B09.03

    DOI: 10.1520/STP33037S


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