| Low cycle fatigue properties of polycrystalline and directionally solidified CM247LC Superalloys were studied at ambient, 760℃, 871℃ and 982℃. At constant total strain, fatigue life of directionally solidified specimens were much longer than that of polycrystalline specimens. The lower Youngs modulus, and so the lower applied stress, of directionally solidified alloys was ascribed as a major source of longer fatigue life of these alloys. When evaluated at constant plastic strain, fatigue life was lowest at 760℃ in both polycrystalline and directionally solidified specime Inhomogeneous shearing of γ`particles by extended dislocations and/or superdislocations at lower temperatures was attributed to be responsible for this behavior. |
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