NEW DEVELOPMENTS IN BRAZING HIGH-TEMPERATURE NICKEL-BASE ALLOYS

The presence of aluminum and titanium in age-hardenablenickel-base alloys introduces difficulties in furnace brazing. Two successful solutions to the problem are presented. One solution was the development of a new palladiumnickel brazing alloy which is self-fluxing in an argon atmosphere and is nonaggressive to the base metal. The second solution is the use of preplaced nickel powder on the surface to be brazed before the introduction of a molten brazing alloy into the joint. By using the latter method with the nickel-base alloys, no flux is required in an argon furnace atmosphere. Tee-brazed joints were used to observe flow, and plug- and cylinder-type joints were used to determine short-time, tensile-shear strengths at 1200 deg F,and stress-to-rupture at 1200 and 1500 deg F. Commercial brazing alloys were also evaluated on Inconel X age-hardenable nickel-chromium alloy in tensile-shear at 1200 deg and in stress-to-rupture at 1200 and 1500 deg F. (auth)