Mechanical properties and deformation mechanisms of Ni−Co-based wrought superalloy via solution−rolling−aging treatment

Abstract

To achieve high strength in Ni−Co-based wrought superalloys, cold-rolling was introduced into the solution and aging treatments. The alloys were characterized and tested using EBSD, SEM, TEM, and tensile tester to analyze their microstructure and mechanical properties at different temperatures, revealing their strengthening and deformation mechanisms. Results indicated that after solution, cold-rolling, and double aging, the alloy contained high-density dislocations, stacking faults, Lomer−Cottrell locks, and nanotwins. The yield strengths of the alloy at room temperature, 923, and 1023 K were 1855, 1406, and 1086 MPa, respectively, which were significantly higher than those of typical Ni-based wrought superalloys. This enhancement was primarily attributed to the dislocations and nanotwins. Additionally, during the cold-rolling process, plastic deformation mainly occurred through dislocation slip. With the temperature increasing to 923 and 1023 K, the main deformation mechanisms of the alloy transformed to stacking faults and nanotwins, respectively.