Preparation method for high-density fine grain tungsten copper alloy

Abstract

The invention relates to a preparation process for high-density fine grain tungsten copper alloy. The alloy consists of 50 to 90 percent of W and 10 to 50 percent of Cu. The preparation process synthesizes the mechanical alloying advantage of ball milling and dry milling and the quick grain refining advantage of wet milling in the aspect of preparation of powder, and also synthesizes the liquid phase rearrangement advantage of liquid phase sintering and the forming pressure-reducing and sintering time-shortening advantages of solid phase hot-pressed sintering in the aspects of sintering process, so the high-density fine grain tungsten copper alloy with the relative density of 99.2 to 99.5 percent and tungsten crystal grain of 0.3 to 0.8 micron is prepared at the relatively low sintering temperature. The tungsten copper alloy prepared by the preparation process is uniform in structure, low in oxygen content, small in crystal grain and high in density; and the process is simple and the used equipment is industrial common powder manufacturing equipment and sintering equipment, so industrialized production is facilitated.

Description

technical field [0001] The invention relates to a preparation method of a tungsten-copper material, in particular to a preparation method of a high-density fine-grained tungsten-copper alloy. The invention belongs to the technical field of powder metallurgy material preparation. Background technique [0002] Tungsten-copper composite material is a composite material composed of tungsten with high melting point and low thermal expansion coefficient and copper with high electrical conductivity and high thermal conductivity. It combines the characteristics of tungsten and copper. Therefore, it is widely used in electronic packaging materials and heat sinks. Materials, vacuum technology and aerospace fields, etc. The ideal structure of tungsten-copper alloy used as electronic packaging and heat dissipation materials should be high density, uniformly dispersed tungsten particles form a continuous skeleton, solidified Cu fills the pores of the tungsten skeleton, and presents a co...

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Problems solved by technology

[0004] In order to solve the problems existing in the traditional process, many new processes for preparing tungsten-copper materials have been studied at home and abroad. The common feature of these new processes is to prepare ultra-fine tungsten-copper composite powder with greater sintering activity, and then through the traditional cold pressing The sintering process produces high-density tungsten-copper materials. For the preparation of ultra-fine tungsten-copper composite powders, there are mainly two chemical methods and mechanical methods. The chemical method is to form powder by spray drying the precursor solution containing tungsten and copper. Or use a precipitant to generate a precipitate, then bake it to form a mixture of tungsten oxide and copper oxide, and then reduce it with hydrogen to generate nano-tungsten-copper composite powder, such as patents 200710118440.7, 200710024801.1, 201110007251.9, etc. Although these methods can prepare nano-tungsten-copper composite powder Powder, but the process is complicated, and corrosive substances are used or generated in the process (such as concentrated nitric acid, concentrated sulfuric acid, nitrogen dioxide, etc.), which requires high equipment and is easy to cause environmental pollution

The mechanical method is mainly to pulverize tungsten-copper composite powder through high-energy ball milling, such as patent 03143145.3, to prepare nanocrystalline tungsten-copper composite powder through high-energy wet milling. However, in the process of high-energy wet milling, due to the addition of ball milling media and surfactants, It is easy to pollute the powder. On the other hand, these reagents form a liquid film on the surface of the particles, which hinders the mechanical alloying of tungsten copper.

In addition, in these processes, the production is mainly based on the generation of nano-tungsten-copper composite powder. The sintering process is still in accordance with the traditional cold-press forming liquid-phase sintering process. The sintering temperature is generally above 1200 ° C, and the time is generally above 2 hours. It is conducive to the formation of high-density tungsten-copper alloys with fine grains and uniform structure

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