Abstract: This study investigates the influences of brazing temperature, brazing time and brazing clearance on microstructures and high temperature strength of Inconel superalloy. Bonding is performed in a high vacuum furnace using BNi-2 as filler metal. Brazing temperatures employed in this study are 1080 ℃, 1110 ℃ and 1140 ℃. Holding times at the brazing temperature are 5~min, 15~min and 45~min. At the same time, the investigated brazing clearances are 30 μm, 60 μm and 100  μm. Microstructure of the brazed joints is analyzed by means of metallography, scanning electron microscope (SEM). The high temperature tensile strength and microhardness are evaluated at different brazing parameters. The results show that fracture occurs wholly within the braze metal. Deformation appears to be confined to the braze metal with the base metal, showing very little plastic deformation. Brazing time shows to play the important role in the brazing parameters. The peak of microhardness is at the centerline of braze region. Induction heating has little effect on the base materials.

Key words: Vacuum brazing, Inconel superalloy, Brazing parameter, Microstructure, High temperature strength, Microhardness