Hybrid welding methods for advanced materials

激光焊接技术的最新进展带来了新的能力，可以控制热和填充材料的输送到被连接的部件。高频扫描和激光与复合激光焊接中的弧焊焊枪相结合等新技术使连接更广泛的材料具有更大的灵活性。现代光纤激光器的总功率和能量密度还可以在不过度加热周围材料的情况下实现高连接速度，这对于成功连接现代高强度材料和不同的金属组合至关重要。这项提议将使用一种最先进的混合激光焊接系统来开发加工条件和填充材料，该系统是为结合最新技术而定制设计的。该系统在北美是独一无二的，它结合了一个8kW光纤激光器、一个弧焊焊枪和两个辅助送丝装置，能够在焊接过程中沉积大量的焊缝金属化学物质。熔化熔池的形状将由高频扫描光学器件控制，该光学器件可以将0.2 mm的光斑聚焦到需要加热的位置。这一控制水平将提供加入新材料组合的灵活性，例如用于轻型车辆的铝对钢，以及用于发电设备的锆对钢。此外，还将开发新的超高强度合金，方法是不断调整多条不同金属丝送入熔池的速度，并以不同的化学成分评估沿一个接头长度方向的熔敷材料性能。这将实现“材料快速成型”的概念，可用于快速开发新的填充金属，用于未来的连接应用。此外，这项研究还将对如何有效地应用混合激光焊接参数来连接最困难的材料组合产生新的理解。接头和焊缝金属的性能将使用最复杂的测绘技术进行测试，该技术可以在微观尺度上确定材料的屈服应力和硬度，为可用于工业设计的规范提供详细信息。参与其中的学生不仅将成为应用新制造工艺的专家，还将获得使用电子显微镜进行新测试方法和表征的前沿技能，使他们能够在毕业后推动工业实践。

The latest advances in laser welding technology have brought new capabilities to control the delivery of heat and filler material to the pieces being joined. New technologies such as high frequency scanning, and combining laser with arc welding torches in hybrid-laser welding have enabled more flexibility in joining a broader range of materials. The total power and energy density of modern fiber lasers also enables high joining speeds to be achieved without excessive heating the surrounding materials, and this is vital to successful joining of modern high strength materials, and dissimilar combinations of metals.    This proposal will develop processing conditions and filler materials using a state-of-the-art hybrid-laser welding system that has been custom designed to combine the latest technologies. The system is unique in North America and incorporates an 8kW fiber laser coupled with an arc welding torch and two supplementary wire feeders which enable a vast range of weld metal chemistries to be deposited during welding. The shape of the molten weld pool will be controlled by high frequency scanning optics which can focus a 0.2 mm spot size to the location where heat is required. This level of control will provide a flexibility to join new material combinations such as aluminum to steel for light weight vehicles, and zirconium to steel for power generation equipment. Also, new ultra-high strength alloys will be developed by continuously adjusting the rate of multiple different metal wires fed into the weld pool, and evaluating the deposited material properties along the length of the one joint with varying chemistry. This will realize a `rapid prototyping of materials' concept, which can be used to quickly develop new filler metals for joining applications in the future.    The research will also generate a new understanding of how to effectively apply hybrid-laser welding parameters to join the most difficult combinations of materials. The properties of the joints and weld metals will be tested using the most sophisticated mapping techniques that can determine the yield stress and hardness of material at microscopic scales, providing detailed information for specifications that can be used for design in industry. The students involved will not only become experts in applying new manufacturing processes, but also gain leading-edge skills in new testing methods and characterization using electron microscopy, allowing them to later advance the practices in industry when they graduate.