Elucidating the effects of solution and double ageing treatment on the mechanical properties and toughness of MAR-M247 superalloy at high temperature

In this investigation, solution and double ageing treatment is adopted to improve the elongation of MAR-M247 superalloy. A γ′-film is generated around the script-like carbides within the grain interior and around the particulate carbides at grain boundary (GB). The γ′-film can protect the carbide interface, and accommodate the interface stress state to toughen the superalloy. Therefore its elongation can be increased not only at 1172 K, but also in the creep test at 1033 K/724 MPa. However, the tensile strength is slightly reduced because the γ′-phase becomes coarse. Hence, applying solution and double ageing treatment to MAR-M247 superalloy can efficiently enhance the MAR-M247 superalloy's ductility at high temperature, and make its casting more reliable. It can therefore be used in a heat treatment process for toughening the superalloy.