The effects of machinability of new typcial superalloy on its surface integrity

摘要

Nickel-based superalloy is mostly used as the material of aeroturbine blades for its high strength and high heat-resistance. Equiax crystalline alloys produced by conventional precise casting are strengthened by the regular dispersion of gamma' phase, which enhances the strength and stability but weaken the ductility of alloys. It's found that almost all the damages of equiax crystals such as high temperature creep and heat fatigue damages are related to the grain boundaries perpendicular to the axis of stress. By the newly developed casting technology of directional solidification, the blades can get columnar crystals with preferred (001) orientation parallel to the stress axis, thus increases the plasticikty, ductility and creep resistance of alloy by eliminating most grain boundaries perpendicular to the stress axis (1).