Surface treatment of DZ4 directionally solidified nickel-based superalloy by high current pulsed electron beam

Surface treatment of DZ4 directionally solidified nickel-based superalloy was carried out by using high current pulsed electron beam (HCPEB) technique. Microstructure changes in modified surface layer were characterized together with their corrosion property. It is found that the treated surface becomes rougher with increasing the number of HCPEB pulse due to the formation of craters occurring preferentially in the interdendritic areas. The thickness of remelted layer increased slightly when more HCPEB pulses applied and reached about 3 μm after 10 HCPEB pulses. The corrosion resistance of modified surfaces exhibited an effective improvement when measured in 0.5 mol/L sulfuric acid solution. The factors that influence the corrosion resistance of DZ4 alloy were discussed by considering the surface purification effect featured by HCPEB surface treatment.