摘要随着微电子行业的行业的快速发展，对封装材料要求也越来越高，而高硅铝合金的高热导率、低膨胀系数等均较符合其要求；本文主要对Al-30Si合金的CMT焊接性能包括焊缝成型、硬度、气密性等进行分析。86466

  首先我们对所用的试验材料进行了拉伸试验，结果表明Al-30Si合金的延伸率仅有3。8%左右，为典型的脆性材料；其次我们对试样用不同的焊接参数进行CMT堆焊试验，分别以不同的焊接速度和送丝速度进行并将焊接后的焊缝制成金相试样进行显微观察气孔和焊缝熔宽、余高、熔深和余高的测量和分析，结果表明经过CMT焊接的Al-30Si合金有较多的气孔且气孔随着焊接速度的增大而减少，同时通过对焊缝宏观参数的分析发现送丝速度在3。0m/min-3。9m/min左右时焊接能得到比较好的焊缝成型，其中在送丝速度3。0m/min，焊接速度为500mm/min的时候焊料具有最好的铺展，形成较美观且气孔较少的焊缝；最后我们对试样进行硬度的测量，分别对焊缝中心和热影响区的硬度进行了测量，研究不同的焊接参数对于焊缝中心和焊接热影响区的硬度的影响，结果表明，焊缝中心的硬度随着送丝速度的提高而降低，而热影响区的硬度随着焊接速度的加快、送丝速度的减慢而增大。

  综上所述，对于Al-30Si合金的CMT焊接在送丝速度为3。0m/min、焊接速度为500mm/min左右能形成气密性较好的焊缝。

毕业论文关键字：高硅铝合金；CMT焊接；焊缝气孔；送丝速度；焊接速度

Abstract With the rapid development of the microelectronics industry, the industry of packaging material requirements are also increasing。 high thermal conductivity and low expansion coefficent of high silicon aluminum alloy are meet their requirements; in this paper, the CMT welding properties of Al-30 Si alloy including weld formation, hardness, porosity ratio were analyzed。

   First, we carried out tensile tests on the test materials,the results show that the elongation rate of Al-30Si alloy is only about 3。8%,which is a typical brittle material; Secondly, we test for the different welding parameters of CMT welding test in different welding speed and wire feeding speed and the weld after welding made of metallographic specimen were measured and analyzed by microscopic observation of porosity and weld width, reinforcement, penetration and reinforcement, the results showed that after Al-30Si alloy CMT welding there are many stoma and porosity and decrease with the increase of welding speed, at the same time, through the analysis of the macro parameters can be found in the weld seam forming better around the 3。0m/min-3。9m/min welding wire feeding speed, in which the wire feeding speed is 3。0m/min, the welding speed is 500mm/min when the solder has the best spreading, forming a weld is beautiful and pores less; we perform hardness measurement of specimen, respectively。 The microhardness of the weld center and heat were measured on different Welding parameters for welding the weld center and the influence of the hardness of the heat affected zone。 The results show that, the hardness of weld center with the increase of wire feed speed decreased, and the hardness of heat affected zone with the slower welding speed is quickened, the wire feeding speed increases。           

To sum up, for the Al-30Si alloy CMT welding in the wire feeding speed of 3。0m/min, welding speed of 500mm/min can form a better gas tightness of the weld line

Keywords:High silicon aluminum alloy;CMT welding; weld porosity; wire feed speed; welding speed

目录

第一章 绪论 1

1。1背景 1

1。2高硅铝合金的制备方法