Abstract

Taking TA15 titanium alloy as the research object, laser welding experiments of are performed on the lock-bottom joints, and the microstructure and tensile performance of the joints are analyzed. The laser welding speed is constant and the laser power is 1000 w, 1300 kw, 1600 kw respectively. The bottom weld width and the width of high temperature heat-affected zone (HT-HAZ) increase significantly as laser power increase. The microstructure of the heat-affected zone (HAZ) is relatively complicated, mainly composed of secondary α, acicular α structure and β. The microstructure at the weld metal is comprised of the martensite α′ and acicular α. The tensile strength, fracture morphology and chemical composition of the welded joint are studied by tensile test, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) analysis techniques. The results show that all the specimens fractured near the heat-affected zone, and the fracture is a ductile fracture in the shape of a dimple. The tensile strength of welded joint decreases with the increase of laser power. When the laser power is 1.0 kw, 1.3 kw and 1.6 kw, the tensile strength is 723 MPa, 705 MPa and 695 MPa respectively, which is 64.55%, 62.95% and 62.05% of the base material strength. EDS results show that Mo and V elements are the strengthening elements, while the burning loss of Mo and V reduce the strength of the joint.

Graphic Abstract

中文翻译：

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激光功率对TA15激光焊接锁底接头拉伸性能的影响

摘要

以TA15钛合金为研究对象，对锁底接头进行了激光焊接实验，分析了接头的组织和拉伸性能。激光焊接速度是恒定的，并且激光功率分别是1000w，1300kw，1600kw。底部焊接宽度和高温热影响区的宽度（HT-HAZ）随着激光功率的增加而显着增加。热影响区（HAZ）的微观结构比较复杂，主要由二级α，针状α结构和β组成。焊缝金属的显微组织由马氏体α'和针状α组成。通过拉伸试验研究了焊接接头的拉伸强度，断裂形态和化学成分，扫描电子显微镜（SEM）和能量色散光谱仪（EDS）分析技术。结果表明，所有试样均在热影响区附近断裂，该断裂为点状的韧性断裂。焊接接头的抗拉强度随着激光功率的增加而降低。当激光功率为1.0kw，1.3kw和1.6kw时，抗拉强度分别为723MPa，705MPa和695MPa，分别为基材强度的64.55％，62.95％和62.05％。EDS结果表明，Mo和V元素是增强元素，而Mo和V的燃烧损失降低了接头的强度。焊接接头的抗拉强度随着激光功率的增加而降低。当激光功率为1.0kw，1.3kw和1.6kw时，抗拉强度分别为723MPa，705MPa和695MPa，分别为基材强度的64.55％，62.95％和62.05％。EDS结果表明，Mo和V元素是增强元素，而Mo和V的燃烧损失降低了接头的强度。焊接接头的抗拉强度随着激光功率的增加而降低。当激光功率为1.0kw，1.3kw和1.6kw时，抗拉强度分别为723MPa，705MPa和695MPa，分别为基材强度的64.55％，62.95％和62.05％。EDS结果表明，Mo和V元素是增强元素，而Mo和V的燃烧损失降低了接头的强度。

图形摘要