The invention relates to a preparation method for a gold-
tin eutectic
alloy foil having a uniform structure. The preparation method comprises: accurately preparing a gold-
tin alloy raw material with a
tin mass percentage of 20% and a gold
mass percentage of 80%; in a non-consumable electrical arc
smelting furnace, under a vacuum degree of 10<-3> Pa, repeatedly carrying out
smelting,
electromagnetic stirring and cooling at least three times to obtain a gold-tin
alloy casting ingot; and carrying out homogenization annealing on the
casting ingot, and then carrying out multi-pass
thermal compression to obtain the gold-tin eutectic foil. According to the present invention, the vacuum electrical arc
smelting, the circular
electromagnetic stirring and the cyclic
thermal compression to prepare the whole lamellar eutectic structure, wherein the eutectic point component does not have the primary phase; and compared with the preparation method in the prior art, the preparation method of the prevent invention has the following characteristics that: the complete alloying is achieved, the strength is high, the
weldability is good, other components are not added or the gold-to-tin ratio is not adjusted, the
welding temperature and the
welding performance are stable, the
welding piece deformation and the force on the welding piece are uniform, the welding piece
cracking condition is not easily generated, the yield is high, the production efficiency is much higher than the production efficiency of the
electroplating method for preparing the gold-tin welding piece, the production cost is reduced, and the preparation method is suitable for
mass production.