Laser Joining of Dissimilar Metallic Materials for Advanced Structural and Engineering Applications

用于先进结构应用的异种金属材料的连接，例如车身、船舶结构、医疗器械等，这对于设计灵活性很重要。这将允许有效地利用不同金属的互补特性，因此，将允许设计工程师推动现有的设计边界，以实现组件的成本效益制造。为了实现全部潜力，至关重要的是设备能量有效地连接这种不同的金属部件。焊接是一种简单而坚固的连接技术，但焊接的热量将通过触发原子在界面上的扩散而引起参与合金之间的界面反应。这将导致金属间化合物的形成，这将使接头变脆和不可用。因此，异种合金组合焊接工艺的开发可以在塑造下一代组件架构和改造制造业方面发挥重要作用。激光熔焊具有热输入可控、热源分辨率高等独特优势。因此，激光熔化工艺提供了控制焊池形状的灵活性，从而控制参与合金的混合。拟议的研究计划旨在制定强大的和变革性的激光连接技术，用于连接不同的异种金属材料组合。本研究将采用基本的科学方法，有系统地识别和了解决定接头冶金特性和机械强度的关键基础工艺因素。拟议的研究计划将研究三种不同的异种合金组合，即铁-铝、钛-不锈钢和镍钛诺-不锈钢。基于与不同工业部门的相关性来选择不同的合金组合。

Joining of dissimilar metallic materials for advanced structural applications, e.g. car body, ship structures, medical appliances etc., is important for design flexibility. This will allow complementary characteristics of different metals to be exploited efficiently and therefore, will allow design engineers to push existing design boundaries for cost effective manufacturing of components. To realise the full potential it is vital to device energy efficient joining of such dissimilar metallic components. Welding is a simple and robust joining technique but the heat of welding will cause interfacial reactions between the participating alloys by triggering diffusion of atoms across the interface. This will result in formation of intermetallic compounds which would make the joint brittle and unserviceable. Therefore, development of welding processes for joining of dissimilar alloy combinations can play an important role in shaping next generation component architecture and transform manufacturing sector. Laser fusion welding has the unique advantage of controlling the heat input and high resolution in applying the heat source. Therefore, laser fusion process offers the flexibility to control the weld pool shape and therefore mixing of the participating alloys. The proposed research programme aims at formulating robust and transformational laser joining technology for joining of different dissimilar metallic material combinations. A fundamental scientific approach will be deployed by systematically identifying and understanding the key underpinning process factors that determine the metallurgical characteristics and mechanical strength of a joint.Three different dissimilar alloy combinations will be studied in the proposed research programme viz. iron-aluminium, titanium-stainless steel and nitinol-stainless steel. The dissimilar alloy combinations are chosen based on relevance to different industrial sector.