Laser welding is one of the most common technologies with various applications in different industries. In this paper, laser joining of the Ti6Al4V alloy and polyethylene terephthalate (PET) as a means of two common materials is discussed. According to the experimental results, the focal length is a very important parameter in this dissimilar laser welding, and because of the low melting point of PET, it is not possible to create welding at low focal lengths. Furthermore, changing the welding parameters such as welding speed and pulse duration changes the temperature field of the molten pool and its surrounding points, as well as the number, distribution, and the shape deformation of the bubbles formed in PET, which plays an important role in welding quality and mechanical strength. The number of bubbles clearly has a significant influence on the surface contact area and the resultant shear load test values. Generally, reducing the surface contact area between PET and the Ti6Al4V alloy evidently reduces the tensile shear load of the joints. The shear load of the joints has had about 40% variation upon changing the focal length. Additionally, the shear load changed only about 10% by changing the pulse duration from 6 to 10 ms. Seemingly, changing the energy density through a variation of focal length has had a higher influence of about 30% than the incident time of laser beam through increasing the pulse duration. Apart from selecting different laser parameters, the measured temperature in ranges between 100 and 120 °C can produce acceptable joints with lower defects.

中文翻译：

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Ti6Al4V与聚对苯二甲酸乙二酯异种激光键合的温度场，缺陷和机械强度的实验研究

激光焊接是最常见的技术之一，在不同行业中具有多种应用。在本文中，讨论了Ti6Al4V合金和聚对苯二甲酸乙二醇酯（PET）的激光接合作为两种常见材料的一种方法。根据实验结果，焦距是这种不同的激光焊接中非常重要的参数，并且由于PET的熔点低，因此不可能在低焦距下进行焊接。此外，改变焊接参数，例如焊接速度和脉冲持续时间，会改变熔池及其周围点的温度场，以及在PET中形成的气泡的数量，分布和形状变形，这起着重要的作用。在焊接质量和机械强度上。气泡数显然对表面接触面积和所得的剪切载荷测试值有重要影响。通常，减少PET和Ti6Al4V合金之间的表面接触面积显然会减少接头的拉伸剪切负荷。改变焦距后，关节的剪切载荷大约有40％的变化。此外，通过将脉冲持续时间从6 ms更改为10 ms，剪切负载仅更改了大约10％。貌似，通过改变焦距来改变能量密度，比通过增加脉冲持续时间而使激光束的入射时间具有更高的影响，约为30％。除了选择不同的激光参数外，在100至120°C的范围内测得的温度还可以产生可接受的接头，且缺陷较少。