7A52铝合金光纤激光焊参数优化及单级时效处理

发布时间：2018-04-30 20:01

  本文选题：7A52铝合金 + 光纤激光焊　； 参考：《内蒙古工业大学》2017年硕士论文

【摘要】：7A52铝合金是中国自行研发生产的高强装甲铝合金,在实际工程应用中通常以焊接结构的形式而存在。但是在以往的焊接过程中焊接气孔、焊缝强度低等问题严重影响了接头的使用性能,激光焊接技术的快速发展则有望解决这些焊接问题。采用光纤激光器,以6mm厚7A52铝合金为研究对象,对其进行焊接,接头形式为对接。以接头抗拉强度为评价指标,采用正交试验方法系统地研究了焊接速度、焊接功率和离焦量对接头抗拉强度的影响程度,运用极差分析手段确定了较优焊接参数组合。焊接参数对接头抗拉强度的影响程度顺序为:RcRaRb,并得到了6mm厚7A52铝合金光纤激光焊较优参数组合:焊接功率5.2kW、焊接速度40mm/s、离焦量为0mm,此参数下的接头抗拉强度为336MPa,接头系数为69.7%,断裂类型属于韧脆混合断裂。在120℃、140℃和160℃三种时效温度下,分别对焊接接头进行了单级时效研究,发现母材与焊缝的硬化曲线变化规律基本一致;时效温度对接头时效硬化过程的影响相当显著,随时效温度的升高,焊接接头的显微硬度变化更加明显,达到峰值时效硬度的时间明显缩短;当时效温度140℃、时效时间16h时,能够获得综合性能更好的焊接接头;在单级时效过程中起主要强化作用的是MgZn2相,在峰时效状态下的主要强化相是细小的η,相和GP区。
[Abstract]:7A52 aluminum alloy is a kind of high strength armored aluminum alloy which is developed and produced by China. It usually exists in the form of welded structure in practical engineering application. However, in the past welding process, such problems as welding porosity and low weld strength have seriously affected the performance of the joint, and the rapid development of laser welding technology is expected to solve these welding problems. The 6mm thick 7A52 aluminum alloy was welded by fiber laser. The influence of welding speed, welding power and defocus on the tensile strength of joints was studied systematically by orthogonal test. The optimum welding parameters were determined by means of range analysis. The influence of welding parameters on the tensile strength of the joint is in the order of: Rc RaRb. The optimum parameters of 6mm thick 7A52 aluminum alloy fiber laser welding are obtained: welding power 5.2 kW, welding speed 40 mm / s, defocus 0 mm. The tensile strength of the joint under this parameter is 336 MPA. The joint coefficient is 69.7 and the fracture type belongs to ductile and brittle mixed fracture. The single stage aging of welded joints at 120 鈩，

本文编号：1825989