摘要6061 属于 Al-Mg-Si 系铝合金，强度中等，具有良好的塑性和优良的耐蚀性，特 别是抗应力腐蚀开裂倾向，焊接性优良，运用范围广。由于薄板铝合金导热系数大， 线膨胀系数大，在焊接过程中易受热源影响产生翘曲变形，故焊接铝及其合金适合使 用热功率大，热源密度集中和保护效果好的焊接方法。80932

激光-电弧复合焊作为先进的材料连接技术，焊接成本低，焊缝成形好，焊接缺 陷少，工艺适应性强，焊接过程稳定，焊接效率大大提高，同时具有阴极清理作用， 很适合焊接铝合金。

本文使用 4043 的铝合金焊丝配合 3mm 6061 铝合金，主要研究焊接电流、电弧 电压、焊接速度以及激光功率对焊缝成形、焊接接头显微组织、显微硬度、气孔倾向 的影响。用金相法和超景深法观察接头微观组织，用显微硬度测试计测量焊接接头的 显微硬度。本试验的条件下，热影响区不存在液化裂纹，焊缝区不存在结晶裂纹。

试验得出焊接电流为 90A，电弧电压为 17。5V，焊接速度为 10mm/s，激光功率 为 1kW 时，焊缝成形最好。

毕业论文关键词: 复合焊 6061 铝合金 焊缝成形 显微组织 显微硬度

Abstract 6061 aluminum alloy belongs to AL-Mg-Si alloy, it has medium intensity, good plasticity and high corrosion resistance, especially great resistance to stress corrosion cracking。 Due to it’s good weld ability, it has been widely used and has boundless prospects。 Because the thin plate of aluminum alloy has high coefficient of thermal conductivity and linear expansion, so it can be affected by heat source easily and cause buckling deformation。 We had better to use a weld method of high and concentrated power with efficient protection。

As an advanced welding method, laser-MIG hybrid welding technique has low cost, can improve weld formation and technology adaptability, reduce weld defect, the process of welding is more stable, the efficiency of welding has been highly improved。 At the same time, the cathode cleaning action of the welding method is very suitable for  weld aluminum alloy。

The study used 3mm 6061 aluminum alloy with 4043 aluminum alloy welding wire。 By changing current, voltage, laser power, welding speed and other parameters to study their influence on weld formation, micro-hardness, micro-structure and porosity tendency。 Using metallographic and to observe the micro-structures。 Meanwhile, the micro-hardness was tested。 Under the circumstance of the experiment, no liquation cracking was founded in the heat affected zone and no solidification cracking was founded in the weld zone。

It is concluded that when the current is 90A, the voltage is 17。5V, the welding speed is 10mm/s, the laser power is 1kW, the best weld formation can be achieved。

Keywords: hybrid welding, 6061 aluminum alloy, weld formation, microstructures, micro-hardness

目录

第一章 绪论 1

1。1 研究背景及意义 1

1。2 激光电弧复合焊应用及研究现状 1

1。3 铝合金焊接性 2

1。4 铝合金焊接方法 4

1。4。1 纯激光焊接铝合金 4

1。4。2 纯电弧焊接铝合金 6

1。5 铝合金激光电弧复合焊工艺 7

1。6 本课题研究内容 8

第二章 试验材料、设备及方法