Microstructure and mechanical properties of the IC10/GH3039 dissimilar electron beam welded joint

Abstract The dissimilar welded joint of GH3039 superalloy and IC10 single crystal Ni3Al-based superalloy was manufactured by electron beam welding, with no defects. The microstructure and mechanical properties were investigated systematically. The results indicated that the microstructure of welded joint was transformed from cellular crystals to columnar crystals and dendritic crystals. The microstructure texture in fusion zone showed strong local grain orientation and high angle grain orientation dominated. The dislocation structures existed in intergranular and intragranular, and the γʹ phases induced the dislocation accumulation. The welded joint possessed high plastic toughness to release stress through its deformation, preventing cracks from occurring. The microhardness of welded joint can averagely reach 288 HV and the tensile strength was 751 MPa, which is higher than that of the GH3039 base metal. The fractography of welded joint is ductile combined with brittle fracture in local area.