Activated soldering of dissimilar materials with amorphous solders

Abstract

The features of soldering of dissimilar materials using amorphous solders (for example, steel–titanium pair) have been investigated. To reduce the soldering temperature below the phase transformation temperature and to retain the advantages of the solution-diffusion junction, compositions for amorphous alloy solders have been developed representing a powder mixture of amorphous solder based on titanium VPr-16 with low-melting solders based on gallium and indium. The efficiency of activated soldering has been tested from the standpoint of mechanical strength using cylindrical butt-soldered samples, the elements of a steel–titanium tube board, and some specific complex structures of heat exchange systems, etc. On the basis of the X-ray spectral analysis of soldered joints using a Camebax micro unit, it is established that the diffusion zone of a soldered joint is about 100 μm. The solder is completely consumed during the formation of the diffusion layer, the independent phase is not retained, which provides high strength properties of the soldered junction. The developed approach to the creation of hard-packed soldered structures from dissimilar materials is basic and has been successfully implemented for a number of other compositions, including the soldering of aluminum, steel, and NiCr; copper and a quasicrystalline Al–Cu–Fe alloy; and titanium and ruthenium. Examples of successful practical implementation of the results are presented.