Hybrid welding methods for advanced materials

激光焊接技术的最新进展带来了新的能力，以控制热量和填充材料的输送到被连接的部件。在混合激光焊接中，高频扫描和结合激光与弧焊炬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金属组合至关重要。该提案将使用最先进的混合激光焊接系统开发加工条件和填充材料，该系统已被定制设计以结合最新技术。该系统在北美是独一无二的，它结合了一个8kW的光纤激光器，加上一个弧焊炬和两个辅助送丝器，可以在焊接过程中沉积大量的焊缝金属化学物质。熔融熔池的形状将由高频扫描光学系统控制，该系统可以将0.2 mm的光斑聚焦到需要加热的位置。这种控制水平将为加入新的材料组合提供灵活性，例如用于轻型车辆的铝与钢，以及用于发电设备的锆与钢。此外，通过不断调整多种不同金属丝送入焊接池的速率，并根据不同的化学性质评估沿一个接头长度沉积的材料性能，将开发出新的超高强度合金。这将实现“材料快速成型”的概念，可用于快速开发用于未来连接应用的新型填充金属。该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绘图技术进行测试，该技术可以在微观尺度上确定材料的屈服应力和硬度，为工业设计提供详细的规格信息。参与的学生不仅将成为应用新制造工艺的专家，而且还将获得使用电子显微镜的新测试方法和表征的前沿技能，使他们能够在毕业后推进工业实践。

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.