硅铝合金激光焊接的仿真及微观分析

发布时间：2018-06-04 19:01

本文选题：硅铝合金 + ANSYS软件　；参考：《电子科技大学》2017年硕士论文

【摘要】：近些年来硅铝合金被广泛用作微波电子封装材料。硅铝合金材料的热膨胀系数小且与电子器件硅板的热膨胀系数相近,密度比柯伐合金等微电子封装材料低,和铝合金一样有着很高的导热系数,通过调整硅在铝中的百分比含量可以制得不同性能的硅铝合金。微波器件属于精密电子器件,体积小,封焊温度不能过高,不适于采用电弧焊等焊接方法。激光具有较高的能量和较小的加热区域允许对电子封装材料进行焊接密封。但是硅铝合金材料中有大块的初晶硅颗粒以及表面附着一层薄的氧化层等因素容易造成激光焊接后腔体的漏气失效,而且焊接工艺参数的控制也影响着焊接的效果。本文首先对微观分析技术进行了概述,对扫描电子显微镜和能谱仪的原理进行了简要的介绍,通过硅铝合金Al4047的二次电子成像与背散射成像的对比,说明了二次电子成像与背散射成像的不同之处,并且简单提及硅铝合金焊缝的线扫描,对线扫描的应用做了介绍。其次,通过对三种不同硅铝合金材料制造的失效的封装腔体进行分析,得到导致腔体漏气失效的原因主要是有两种:1)硅铝合金材料不适合焊接;2)焊接操作不当生成裂纹、气孔、夹渣、焊缝覆盖不完全等缺陷导致封装腔体漏气。通过运用SEM和EDS失效分析手段来对上述两种失效原因进行研究并提出提高产品合格率的手段。再次,通过对硅铝合金4047盖板和铝合金6061壳体组成的微波腔体进行焊接,通过改变焊接的工艺参数,得出了不同的焊接工艺参数对熔池尺寸大小的影响。最后,针对硅铝合金腔体进行了有限元模拟,在ANSYS软件中分别建立硅铝合金平板模型和腔体模型并选择高斯热源作为激光热源模型。通过进行平板模型得出了在指定的焊接条件下平板的温度分布和应力分布,得出了两种不同硅铝合金材料激光焊接时熔池的形状和焊缝两侧的温度和应力分布规律。然后进行了腔体模型的仿真,并对它整体的温度和应力分布图进行分析。
[Abstract]:Silicon aluminum alloys have been widely used as microwave electronic packaging materials in recent years. The thermal expansion coefficient of Si-Al alloy is small and close to that of electronic device silicon plate. The density of Si-Al alloy is lower than that of other microelectronic packaging materials such as Kovar alloy, and the thermal conductivity of Si-Al alloy is as high as that of aluminum alloy. Silicon aluminum alloy with different properties can be prepared by adjusting the percentage content of silicon in aluminum. Microwave device is a precision electronic device with small size and high sealing temperature, so it is not suitable for welding methods such as arc welding. The laser has higher energy and smaller heating area to allow welding sealing of electronic packaging materials. However, some factors, such as bulk primary silicon particles and a thin oxide layer attached to the surface of silicon aluminum alloy, can easily cause air leakage failure of the cavity after laser welding, and the control of welding process parameters also affects the welding effect. In this paper, the principle of scanning electron microscope (SEM) and energy spectrometer (EDS) are briefly introduced, and the comparison between secondary electron imaging and backscattering imaging of Al4047 is given. The difference between secondary electron imaging and backscattering imaging is explained, and the linear scanning of silicon aluminum alloy welds is briefly mentioned, and the application of line scanning is introduced. Secondly, through the analysis of three different kinds of silicon aluminum alloy materials, it is found that there are two kinds of silicon aluminum alloy materials that are not suitable for welding, such as cracks and pores, which are not suitable for welding, and the main reasons are that two kinds of silicon aluminum alloy materials are not suitable for welding, and the main reason is that two kinds of silicon aluminum alloy materials are not suitable for welding. Defects such as slag inclusion, incomplete weld cover, etc., lead to gas leakage in the packaging chamber. By means of SEM and EDS failure analysis, the above two failure reasons are studied and the means to improve the qualified rate of products are put forward. Thirdly, by welding the microwave cavity composed of silicon aluminum alloy 4047 cover plate and aluminum alloy 6061 shell, the influence of different welding parameters on the size of weld pool is obtained by changing the welding process parameters. Finally, the finite element simulation is carried out for the silicon-aluminum alloy cavity. In the ANSYS software, the Si-Al alloy flat plate model and the cavity model are established, and the Gao Si heat source is selected as the laser heat source model. The temperature distribution and stress distribution of the plate under the specified welding conditions are obtained by using the plate model. The shape of the molten pool and the distribution of temperature and stress on both sides of the weld are obtained during laser welding of two different kinds of Si-Al alloy materials. Then, the simulation of the cavity model is carried out, and the distribution of temperature and stress is analyzed.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG456.7

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