超声辅助连接氧化铝陶瓷界面润湿机制及性能研究

发布时间：2018-02-04 07:40

  本文关键词： 蓝宝石 Al-12Si 超声 润湿 剪切强度　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：蓝宝石单晶具备高强度、高硬度、耐磨损、耐腐蚀、耐高温、导热性良好及光透过率高等特性,因此在微电子、光电行业、半导体、航空航天等工业上常作为衬底材料或窗口材料。但由于大尺寸蓝宝石一次成型的难度较大,其本身具备的塑性较差,因而蓝宝石在大尺寸构件及形状要求复杂的领域上的应用受到了限制。解决此问题的方法之一就是采用焊接与连接的方法将小尺寸的蓝宝石连接起来,根据需求制成不同形状的蓝宝石连接件。基于此,本文以蓝宝石单晶作为研究对象,提出在大气环境下能有效快速成形的超声波辅助钎焊方法,通过自行搭建的简易超声连接平台,系统的研究了超声辅助钎焊蓝宝石的可行性、不同超声工艺参数对接头性能的影响规律、超声对焊缝组织的作用机理以及接头组织形貌的演变过程等。试验结果表明,在大气环境下,使用Al及Al-12Si(wt.%)钎料在超声辅助的作用下能实现蓝宝石之间的快速、可靠连接。在一定范围内,接头的剪切强度随着超声作用时间和超声功率的增加而增强,这是因为两者的提高能有效改善钎料在陶瓷表面的润湿,减少接头中气孔等缺陷的产生,增强了界面化学反应。但当超声作用时间过长(≥60 s)及超声功率过大(≥300 W)时,接头强度反而有所减小。研究发现,该现象是由于在温度较高的条件下,长时间高功率的超声作用会对蓝宝石基体产生损伤,并诱发微裂纹。Al作为钎料,超声时间为5 s-60 s时,接头最大剪切强度为60.14 MPa。Al-12Si合金作为钎料时,超声时间为25 s时接头剪切强度达最大值,为102.22 MPa。蓝宝石在大气环境下能够实现可靠连接的关键在于功率超声的空化效应与声流作用。借助超声空化,钎料表面的氧化膜被打碎并随声流移除,从而在蓝宝石表面实现良好的铺展和润湿,同时超声促进蓝宝石表面氧化铝外延生长,促进反应润湿的发生。超声促进熔融钎料对基体材料产生侵蚀作用,大量的基体氧化铝颗粒扩散进入焊缝,在界面处形成榫形结构。此外,Al-12Si作为钎料时,超声诱导焊缝内元素再分布,在界面处形成Al-Si-O三元相,在接头三维空间中形成自支撑结构。超声促使剥落的母材氧化铝颗粒及诱发的蓝宝石表面外延生长形成的纳米陶瓷新相的共同生长形成最终的接头。
[Abstract]:Sapphire single crystals with high strength, high hardness, wear resistance, corrosion resistance, high temperature resistance, good thermal conductivity and high light transmittance, so in the microelectronics, optoelectronic industry, semiconductor, Aerospace and other industries are often used as substrate materials or window materials. However, due to the difficulty of forming large sapphire at one time, the plasticity of sapphire itself is poor. Therefore, the application of sapphire in the field of large size components and complicated shape requirements is limited. One of the methods to solve this problem is to connect small size sapphire by welding and joining. Different shapes of sapphire connectors are made according to the requirements. Based on this, a supersonic assisted brazing method for rapid prototyping in atmospheric environment is proposed, in which sapphire single crystal is taken as the research object. The feasibility of ultrasonic assisted brazing of sapphire is systematically studied through a simple ultrasonic connection platform. The influence of different ultrasonic parameters on the joint performance is studied. The mechanism of ultrasonic action on weld microstructure and the evolution process of joint microstructure. The experimental results show that, in atmospheric environment, using Al and Al-12SiWt.) brazing filler metal can realize the speed between sapphire and sapphire. Reliable connection. In a certain range, the shear strength of the joint increases with the increase of ultrasonic time and ultrasonic power, because the increase of both can effectively improve the wetting of solder on the ceramic surface, The formation of porosity and other defects in the joint is reduced, and the interfacial chemical reaction is enhanced. However, when the ultrasonic action time is too long (鈮，

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