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摘要体积分数为 70%的 SiCp/Al 复合材料因具有高热导率、高比刚度、低热膨胀系数、低密度等优点，在军事防弹、航空航天、电子封装等行业具有广泛的运用。但由于 70%的SiCp/Al 复合材料具有很高含量的 SiC陶瓷颗粒，增强相与钎料的物理化学性质差别大，焊接性很差。因此成功解决 SiC 颗粒增强铝基复合材料的焊接具有重要的理论意义和实用价值。对 70% SiCp/Al 复合材料采用 Al-Si-Cu-Ti-In 钎料在不同温度、保温时间和压力下进行真空钎焊。结合光学显微镜，扫描电镜、能谱分析仪和万能试验机对接头组织、断口形貌、 接头力学性能进行了分析。 结果表明： （1） 钎焊温度为600℃， 保温时间为 90min，压力为 6MPa 的条件下，所得接头具有最高剪切强度 72.1MPa。该焊缝成型美观，组织均匀致密，没有脆性 Al4C3生成。（2）钎焊温度过高或过低都会降低钎料的润湿性，影响其在界面的铺展，所以试样会出现接头强度随温度升高而增加至峰值后缓慢降低的现象。（3）保温时间为60min 时获得的接头强度相对较高，在这之后随保温时间增加强度明显下降。这是因为保温时间过长会使接头氧化膜增多，阻碍钎料铺展影响焊缝质量；若保温不足，钎料来不及扩散，流动性差导致焊缝难以形成。（4）钎焊时施加一定的压力对焊接效果有显著的提升。原因在于一定压力能够使钎料和复合材料紧密连结，增加了钎料的润湿性和流动性，从而得到的接头组织分布紧密均匀。（5）在对该进行断口分析时发现高强度试样的断裂是发生在焊缝的韧性断裂，而低强度的断裂往往发生在接头处。28642
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毕业论文关键词 70% SiCp/Al 复合材料 真空钎焊 复合钎料
Title Aluminum solder wetting behavior of SiC ceramicsand binding mechanism Interface ResearchAbstractVolume fraction of 70% SiCp / Al composites due to a high thermal conductivity,high specific stiffness, low thermal expansion coefficient, density, etc., in themilitary bulletproof, aerospace, electronics packaging and other industries witha wide range of use. But because 70 percent of SiCp / Al composites with high contentof SiC ceramic particles, and enhance the physical and chemical properties of phasedifference solder large, poor welding. Therefore, the successful resolution ofSiC particle reinforced aluminum matrix composites welding has importanttheoretical and practical value.To 70% SiCp / Al composites using Al-Si-Cu-Ti-In vacuum brazing fillermetal at different temperatures, holding time and pressure. In combination withoptical microscopy, scanning electron microscopy, energy dispersive spectroscopyand universal testing machine joints, fracture morphology, mechanical propertiesof joints were analyzed. The results showed that: (1) the brazing temperature is600 ℃, holding time of 90min, the pressure for the next 6MPa conditions, theresulting joint has the highest shear strength of 72.1MPa. The weld appearance,uniform and compact organization, no brittleness Al4C3 generation. (2) solderingtemperature is too high or too low will reduce wetting and spreading its influencein the interface, so that the sample will be slowly reduced joint strength increaseswith increasing temperature after the first phenomenon solder. (3) holding time60min joint strength obtained when relatively high, after which the strengthincreases with incubation time decreased. This is because the holding time is toolong will increase the joint oxide film, hinder the solder spreading influenceweld quality; if insufficient insulation, diffusion brazing too late, resultingin poor liquidity is difficult to form the weld. (4) put some pressure when soldering to welding results have significantly improved. The reason is that somepressure can make solder and composites closely linked, increasing the solderwettability and fluidity, thereby joint tissue distribution obtained even close.(5) were at the high fracture analysis found that the fracture strength of thesample occurs in the weld fracture toughness, and low-intensity fracture oftenoccurs in the joints.
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