Characteristics of high temperature rupture of a cast Ni-based superalloy M963

The rupture behavior of a cast Ni-base superalloy M963 at high temperature has been investigated. The microstructure examination shows that there exis ts a large amount of the carbide and gamma-gamma ' eutectic, which is very harmful to the mechanical properties of M963 superalloy. The tensile streng th of M963 superalloy both at room temperature and at high temperatures is higher than that of K17G alloy, but the tensile ductility of the former is much lower than that of the latter. In tensile fracture process with the hi gh strain rate, the open carbides are the initiation site and the carbide/m atrix interface is the propagation path of cracks. But in fracture process with the low strain rate, the carbide/matrix interface and cast microvoids are the initiation sites, and the carbide/matrix interface is the propagati on path of cracks. The effective ways to improve ductility of M963 superall oy are also suggested.