Microstructure and properties of a nickel-base superalloy deposited metal

The microstructure and mechanical properties of a nickel-base superalloy deposited metal were studied by means of thermodynamic calculation, optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results indicate that the nickel-base superalloy deposited metal in test was composed of columnar-like NiCr austenitic. There were a few phase, MC carbides and Laves phase in the intergranular of deposited metal. And most of alloying elements in the deposited metal segregated, especially, Mo, Al, Si and Nb were rejected in the intergranular liquid upon solidification, Fe concentrated in grain cores. However, Cr did not apparently segregate. The deposited metal with no cracks, holes and other defects had high strength and good toughness, and its fracture pattern in tensile and impact test was plastic with dimple fracture morphology.