STP890

    Physical Metallurgy and Mechanical Properties of Aluminum Alloys Containing Eight to Twelve Weight Percent Iron

    Published: Jan 1986


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    Abstract

    New aluminum alloys with improved temperature capability have been under development during the last decade for a variety of aerospace applications. Prolonged aerodynamic heating of unprotected aluminum surfaces at relative velocities greater than Mach 2.0 produces fast degradation in the mechanical properties of currently available aluminum precipitation-hardened alloys. One alloy system which demonstrates improved 600 K strength properties and has received considerable attention is that based on Al-8(weight percent)Fe alloy (Al-8Fe) with various ternary additions. This paper reviews the physical metallurgy of aluminum-iron alloys, particularly the effect of increasing solidification rate on the crystallography of the metastable phases, and, finally, the effect of “rapid” solidification at cooling rates of ≈ 106 K/s. The current pilot production methods used for producing these alloys, in engineering quantities, include air atomization, inert gas atomization, and chill-block planar flow casting—all processes having somewhat unique characteristics and producing unique microstructures in the compositional range of 8 to 12% iron, by weight, with ternary additions. Aspects of the differences in these processes in relation to the physical metallurgy of the alloy systems are discussed. In this paper the consolidation of rapidly solidified powders is discussed, demonstrating the relationship between consolidation parameters and the evolution of acceptable mechanical properties for engineering use.

    Keywords:

    aluminum alloys, 8 to 12% iron aluminum alloys, elevated-temperature aluminum alloys, rapid solidification, powder metallurgy, mechanical properties


    Author Information:

    Skinner, DJ
    Senior metallurgist and director, Metals and Ceramics Laboratory, Allied Corp., Morristown, NJ

    Okazaki, K
    Professor, University of Kentucky, Lexington, KY

    Adam, CM
    Senior metallurgist and director, Metals and Ceramics Laboratory, Allied Corp., Morristown, NJ


    Paper ID: STP33031S

    Committee/Subcommittee: B09.02

    DOI: 10.1520/STP33031S


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