A high-efficiency die-casting preparation method of ultra-thin gold-tin eutectic material

Abstract

The invention relates to an efficient die-casting preparation method for an ultrathin Au-Sn eutectic material, and belongs to the technical field of metal material preparation. The preparation method includes the following steps that an Au-Sn eutectic alloy raw material with the mass percent of Sn being 20% and the mass percent of Au being 80% is accurately prepared; the Au-Sn raw material is subjected to vacuum electric arc smelting under the condition that the vacuum degree reaches 6*10<-4>Pa, and electromagnetic stirring is further added to obtain an Au-Sn alloy die-casting ingot of the regular eutectic structure without a primary phase; the die-casting ingot is subjected to die-casting formation in a hot chamber die-casting machine; and a die-casting sheet is subjected to homogenizing annealing, and accordingly the ultrathin Au-Sn eutectic material can be obtained. According to the efficient die-casting preparation method, a mother alloy vacuum electric arc smelting one-step die-casting sheet formation technology is adopted to successfully obtain the ultrathin Au-Sn eutectic material of the uniform eutectic point component structure, the prepared product achieves complete alloying, the rate of finished products is high, components are stable, strength is high and welding performance is good. The designed preparation method is high in preparation efficiency, short in preparation process, low in cost and suitable for batch production.

Description

Technical field [0001] The invention relates to a preparation method of a difficult-to-deform eutectic alloy material, in particular to a high-efficiency die-casting preparation method of an ultra-thin gold-tin eutectic material; it belongs to the technical field of metal material preparation. Background technique [0002] Au-tin eutectic materials have the characteristics of high strength, excellent oxidation resistance, good thermal fatigue and creep resistance, low melting point, and good fluidity, so they are widely used in microelectronics and optoelectronic packaging. However, there is a coarse dendritic primary phase (ζ-Au 5 Sn), eutectic two-phase ζ'phase Au at room temperature 5 Both Sn and δ-phase AuSn phases are brittle phases with hexagonal structure, resulting in poor deformation processing properties of Au-Sn eutectic alloys. It is difficult to prepare and shape them by conventional processing methods, which greatly restricts its production and application. At prese...

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Problems solved by technology

Patent CN1026394C introduces the laminated rolling-diffusion alloying method. This method first obtains laminated foils by cold rolling, and then conducts diffusion annealing of the gold-tin layer to finally obtain gold-tin alloy foils. However, the Au80Sn20 prepared by the laminated diffusion method There is a problem that the alloy solder cannot be completely alloyed

Japanese patent JP5-177380 proposes that in the process of smelting Au80Sn20 eutectic alloy, a small amount of Pd or Pt is added to improve the forming ability while reducing the wettability of the alloy. At the same time, the change of the composition makes the welding process unable to be stably controlled.

Using the above method to prepare gold-tin eutectic materials, there are many subsequent processing procedures, and at the same time, gold-tin eutectic alloys are prone to cracking during thermal processing, and the quality of solder pieces cannot be accurately controlled.

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