Revealing the Formation of Recast Layer around the Film Cooling Hole in Superalloys Fabricated Using Electrical Discharge Machining

A film cooling hole is an efficient and reliable method, which widely used in aeroengine turbine blades to effectively improve the thrust–weight ratio of engine. Electrical discharge machining most common manufacturing process for holes. Due rapid quenching after high-temperature melting, a certain thickness recast layer will be formed vicinity wall. The microstructure considered important factor affecting performance single-crystal blades. Generally, has been thought as one main reasons failure Accordingly, formation interesting issue revealed. In this work, using electrical on superalloy studied with TEM. It found that state supersaturated solution structure epitaxially grown from matrix, many dislocations were observed therein.