A. Rabinkin, Metglas Inc. , Hitachi Metals, Morris Plains, NJ
Amorphous Brazing Foil at Age of Maturity
By Anatol Rabinkin, Metglas Inc., Hitachi Metals
This paper is an updated and detailed review of advances in amorphous metal brazing foil applications and associated technical issues. Most of these applications are made when joining thin-walled 3-dimensional honeycomb structures where erosion issues are of major concern. The major emphasis is to provide practical guidance for the optimization of the brazing processes. That includes a selection of proper compositions and a choice of brazing cycle conditions that result in brazed joint microstructures with best possible properties. The base materials used in these examples are various stainless steels and superalloys. A unique and important case of ferritic steel/BNi-5a joint strengthening is also described. This strengthening phenomenon occurs due to discovered segregation of small particles of Nix Aly phase in the base metal. The segregation is a result of a diffusion reaction between nickel coming from the BNi-5a and the aluminum of the base metal. The segregated particles form a regular pattern similar to that existing in classical superalloys with the segregated γ-prime phase. Finally, the description is given to the huge potential for amorphous metal brazing foil existing in the vast and quickly expanding field of environment protection associated with auto and power production industries.
