STP520: Test Results of Fatigue at Elevated Temperatures on Aeronautical Materials

    Vidal, GP
    Research leader and research technician, Office National Etudes et Recherches Aérospatiales (ONERA),

    Galmard, PL
    Research leader and research technician, Office National Etudes et Recherches Aérospatiales (ONERA),

    Pages: 10    Published: Jan 1973


    Abstract

    This paper shows how fatigue tests at elevated temperature solve many problems pertaining to aeronautical materials. Prolonged periods (5000 or 10 000 h) at 150 C (302 F) did not diminish the fatigue limit at 150 C (302 F) of the aluminum alloy 2618-T6. Consequently, the aerodynamic heating of airframes at Mach 2 does not reduce the fatigue limit of this alloy.

    The “bright shot” or shot-peened surface conditions do not increase the hot-fatigue limit of a heat-resistant alloy. The Office National Etudes et Recherches Aérospatiales (ONERA) process for the chromaluminization of the heat-resistant alloy Inconel 713 does not modify the fatigue limit at 700 C (1290 F). Similarly, gases resulting from kerosine (0.5 percent sulfur) combustion do not reduce the hot-fatigue resistance of four heat resistant alloys. The fatigue characteristics of various superalloys— unidirectional or composites made by the ONERA process—at 800 C (1470 F)—are equal to or even superior to those classic heat-resistant alloys, cast or forged. A cermet of 50 percent of chromium and 50 percent of alumina retains, even at 1200 C (2190 F), a resistance to fluctuating flexure stresses of 69 ± 49 MN/m2 (10 ± 7 ksi).

    Keywords:

    test equipment, fatigue tests, high temperature tests, fatigue (materials), aluminum alloys, chemical machining, heat resistant alloys, surface hardening, oriented fiber composites, cermets, aerospace engineering


    Paper ID: STP38867S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP38867S


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