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钨-石墨高温钎焊接头再熔化温度的研究

INVESTIGATION ON THE REMELT TEMPERATURE OF TUNGSTEN-GRAPHITE HIGH TEMPERATURE BRAZED JOINT

  • 摘要: 本文对钨-石墨高温钎焊接头的再熔化温度进行了研究.如用钛基钎料(Ti-10Ta)在真空中钎焊的温度为1600-1900℃.钎焊接头的再熔化温度达2500-3000℃。文章讨论了钎焊时间、钎焊温度、钎焊间隙及焊后扩散处理对钎焊接头再熔化温度的影响。结果表明,扩散处理及钎焊间隙对钎焊接头的再熔化温度有强烈的影响。文章还重点讨论了获得高的再熔化温度的钎焊接头的机理。研究表明,钎焊时,发生了钛与石墨的反应,形成了高熔点的TiC相;同时,钎焊接头中的其余成分也发生了变化,已不同于原始的钎料成分:钨溶解到钎焊接头中;钽含量有所提高等等。从而,钎焊接头的成分就由高熔点的TiC相和Ti-Ta-W难熔合金所组成。这样,在相应工艺的配合下,可得到高的再熔化温度(2500-3000℃)。

     

    Abstract: The remelt temperature of the tungsten-graphite brazed joint is studied. The titanium-base filler alloy, e.g, Ti-10%Ta, is used. The temperature of brazing in vaccum is in the range of 1600~1900℃. The remelt temperature of the brazed joint is 2500~3000℃. This paper discusses the effect of brazing time, brazing temperature, brazing gap and diffusion treatment on the remelt temperature of the brazed joint. Results show that both the diffusion treatment and the brazing gap affect strongly on the remelt temperature. The mechanism of high remelt temperaiure brazed joint is thoroughly discussed. Theoretical and practical study show that reaction between graphite and titanium takes place during brazing, forming TiC phase of high melting point. Simultaneously, the composition of the rest part in the brazed joint is changed and is different from that of the original brazing filler metal:tungsten is dissolved, tantalum is increased, etc. The composition of the brazed joint is then made up of the TiC phase of high melting point and the refractory alloy of Ti-Ta-W. Thus by applying appropriate brazing technique, a joint of high remelt temperature(2500~3000℃) is got.

     

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