Dissimilar Joining of Heat Treatable Copper alloy with Stainless Steel

A B S T R A C T Precipitation hardening stainless steel and copper chromium zirconium alloy are age hardening materials used in ITER, aerospace and plasma physics. Dissimilar vacuum brazing was carried after in solutionised condition to retain the maximum possible mechanical properties of both the alloys. A novel differential temperature vacuum brazing method coupled with heat treatment was evolved for the same and proved by experiments. The brazing experiment was carried out with a special heater + furnace assembly where the precipitation hardening stainless steel part was at 1040°C and copper chromium zirconium alloy part was at 980°C which where matching with solutionising temperature of both the alloys. Immediately after brazing (brazing cycle = solutionising cycle) the samples were quenched from brazing temperature by inert gas. Filler material used in the study was gold-18% nickel alloy. Aging treatment was carried out at 496°C for 4 hours after brazing. Parameters for maximum joint strength and maximum mechanical properties of precipitation hardening stainless steel and copper chromium zirconium alloy were arrived and discussed in detail. Resultant joint strength, microstructure and hardness results were included