Technical research on recycling waste blades of single crystal superalloy through ultrasonic alkali cleaning combined with electron beam smelting

Abstract

The waste blades of single crystal superalloys have not been formally applied on a large scale, resulting in serious waste. This study proposes to treat the waste blades through ultrasonic alkali cleaning combined with electron beam smelting (EBS). The theoretical model is proposed to study the elements volatilization, which provides a reference for controlling the alloy composition. After EBS, the secondary dendrite spacing and the size of γ′ phases of DD5 alloy is significantly reduced. The EBS technology can effectively reduce the element segregation in superalloys, especially W and Mo elements. The purity of DD5 revert alloy after EBS is consistent with or even exceeds that of DD5 virgin alloy. Especially for the removal of ceramic shell and core materials in the waste blades, EBS has a new technological advantage. Under the combined action of Marangoni effect and buoyancy, the inclusions floating to the melt surface can not only be directly decomposed by the bombardment of the electron beam, but also can be dissolved under the condition of local melt superheating.