The Effect of Revert Addition on Microstructure and Mechanical Properties of K418 Ni-base Superalloy

Abstract

The paper utilized vacuum induction melting furnace to smelt three kind of nickel base superalloys as the research subject. It investigated the effect of revert addition on microstructure and mechanical properties of K418 Ni-based superalloy by means of XRD phase test, microstructure observation and tensile test. The original microstructure of material showed dendrite structure, the main phase of K418 is Cr1.12Ni2.88, strengthening phases are Ni3Al, Ni0.9Nb0.1 and Al0.5Fe0.5. The tensile experiment showed when recycled alloy proportion is less than 50%, it had slightly influence on mechanical properties of materials, and it has a good cyclic utilization rate. In view of the high cost of the superalloy, its cyclic utilization is friendly to the environment and it reduces the waste of resource. Introduction Nickel base superalloy is one classification of the superalloys that have been developed for elevated temperature services, where relatively severe mechanical stresses are encountered and surface stability is frequently required [1]. Because of its high strength, oxidation resistance, radiation resistance, hot working performance, welding performance, good fatigue properties, fracture toughness and plastic, etc and it contains little scarce resources elements Co, Ni-based superalloy has been widely used in field of the aerospace, power generation, ships, oil and chemical industry [2] [3]. In recent years, facing the bottleneck of Ni, Co resources, the scholars have carried out the research work on recycling of Ni, Co scrap metal complex oxide, waste materials of Ni-base alloy and other secondary resources, in order to resolve the problems of mineral resources bottleneck and the high value of recycling resources [4]. What is more, some literatures showed that the mechanical properties of recycling superalloy are insignificantly influenced by recycled material [5] [6]. Fortunately, these results might indicate that recycled superalloy could also be used in gas turbine engines, and by this way, the efficient recycling of material can be better.