JOINING OF HASTELLOY-X TO INCONEL-718 USING AN INFRARED PROCESS

Joining of Hastelloy X to Inconel 718 by a rapid infrared processing t echnique has been investigated al 1150 degrees C using a nickel-based brazing alloy AMS 4777, Ni-7Cr-3Fe-3.2B-4.5Si-0.06C in wt.%. With-this infrared technique, joining typically was completed in seconds in amb ient argon. The effects of the infrared joining time on the joint and base material microstructures, elemental distribution within the micro structures and the resulting joint shear strength were investigated. R esults show that excellent joint shear strengths of as high as 503 MPa were obtained when processed at approximately 1150 degrees C for 120 s, Micro-structural examinations of the joint with an optical microsco pe and a scanning electron microscope indicate that good wetting exist ed between the brazing alloy and both Hastelloy X and Inconel 718. The braze-affected zone width increased with increasing joining time but did not show a direct correlation with the joint strength. Hastelloy X and Inconel 718 exhibited no noticeable change in microstructures due to the rapid heating cycle of infrared processing.