Microsegregation of Alloying Elements at Deformation-Induced Stacking Faults in a Powder Metallurgy Nickel-Base Superalloy

Specimens cut from a powder-metallurgy manufactured disk of the Russian nickel-base superalloy VZh178P have been tested for tensile strength at room temperature and creep strength at 750°С. Transmission electron microscopy has shown that stacking faults and microtwins form in both cases during plastic deformation of the alloy. Creep testing at 750°C causes segregation of alloying elements Cr, Co, Mo, and W at stacking faults, resulting first in a Suzuki atmosphere and then in the nucleation and growth of TCP particles with (Co, Cr)3(Mo, W) stoichiometry.