【作者】 吕志勇；

【导师】 亢世江；

【作者基本信息】 河北工业大学 ， 材料加工工程， 2004， 硕士

【摘要】 金刚石膜具有优异的综合性能，具有非常广阔的应用前景，特别是在机加工领域。但在金刚石厚膜钎焊刀具的加工过程中，还存在许多问题。针对钎料制备过程中存在的钎料制备过程复杂、成形困难等问题，本课题开发了一种制备过程简单，焊接效果好的新型钎料——活性涂层钎料。 活性涂层钎料是运用真空磁控溅射镀膜技术，在一定的溅射电压、溅射电流和溅射时间条件下，在Ag-Cu钎料箔片表面溅射活性元素Ti。通过扩散退火来提高活性涂层与基体材料的结合力，得到了试验用钎焊金刚石膜和硬质合金的活性涂层钎料。利用制备的钎料，采用真空钎焊的方法，在钎焊温度为850℃、真空度不低于5×10^-2Pa和保温10min的条件下，实现了CVD金刚石厚膜与硬质合金的牢固连接。利用扫描电镜分析发现，经退火后的钎料，活性元素Ti均匀分布于钎料表面；金刚石与硬质合金钎焊接头中，活性元素Ti原子与金刚石表面的碳原子在高温下反应生成了连续的TiC膜。分析表明：金刚石膜与钎料之间是通过活性涂层元素与金刚石膜生成的TiC膜、钎料在金刚石膜表面的机械钉轧作用连接在一起的。 采用所制备的钎料钎焊金刚石膜，针对钎料与金刚石膜、硬质合金的热膨胀系数相差大，在钎焊冷却过程中，接头内部产生很大的热应力，冷却速度对残余应力影响大，本文利用现代数值模拟方法，对钎焊冷却过程中，不同冷却速度条件下接头中残余应力进行了模拟计算；得到了不同冷却速度条件下，接头内部残余应力大小变化规律和残余应力场的分布规律。更多还原

【Abstract】 Diamond film has excellent combination properties, so it has great application foreground especially in machining. But there are many problems in the process of making brazing diamond film tools. In order to solve the problems of complexities and shaping difficulties in preparation of brazing filler metal, we exploit a new one with fewer processes in shaping and well brazing results. We called it active coated brazing filler metal.Using technology of magnetron sputtering in vacuum, we prepared the active coated brazing filler metal: Ti was sputtered onto the Ag-Cu alloy foil under proper sputtering voltage, sputtering current and sputtering time. Through annealing, the binding force between the coated film and the base foil was strengthened. And we acquired the brazing filler metals used in the test of brazing diamond film and cemented carbides. Using this brazing filler metal, firm binding of CVD diamond thick film and cemented carbides formed by vacuum brazing under the condition that brazing temperature at 850℃, pressure below 5×10-2Pa and keeping 10 minutes. By the SEM photograph, we found that the active element Ti evenly distributed on the surface of the brazing filler metal. And in the joint, a continuous TiC film was generated by Ti reacted with carbon on the surface of diamond film. The TiC film and mechanical anchoring was the bridge linking diamond film and the brazing filler metal.Because of great difference among the expansion coefficient of diamond film, cements carbides and the brazing filler metal, high residual stress would generated in the brazing joint. The cooling velocity has great influence on the residual stress. Using of Finite Element Method, numerical simulation of residual stress generated with different cool velocity during the cooling process was done. We obtain the rules of the variation of residual stress and the distribution of stress field.更多还原