Sample records for alloy-m-813

  1. In-sodium creep behavior of alloys M-813 and Nimonic PE16

    The in-sodium biaxial creep deformation of internally pressurized tube specimens of alloys M-813 and Nimonic PE16 was measured at 6500C under constant stress conditions after 4000 hours of sodium exposure. Each alloy had specimens at two different stress levels, viz., 0 and 165 MPa (24,000 psi). The data showed negative diameter changes at zero stress, which were attributed to material densification associated with precipitation. Although material densification was also seen in comparable in-argon experiments, the in-sodium creep strains at 165 MPa and 6500C were much lower than the corresponding in-argon values. The higher creep strains in argon are explained on the basis of two parallel mechanisms involving oxygen, which is present at a low level in sodium (1 ppM) as compared with approximately 1000 ppM in the argon environment. The trends in the current data are consistent with observations by earlier authors. Sodium exposure of Nimonic PE16 also resulted in 4 μm deep intergranular penetration, which did not have any apparent effect on its biaxial creep behavior