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

对于先进的结构应用，如汽车车身、船舶结构、医疗器械等，不同金属材料的连接对于设计灵活性是非常重要的。这将使不同金属的互补特性得到有效利用，因此，设计工程师将能够突破现有的设计界限，以实现具有成本效益的部件制造。为了实现全部潜力，对这种不同金属部件的设备节能连接至关重要。焊接是一种简单而坚固的连接技术，但焊接的热量会引发原子在界面上的扩散，从而在参与的合金之间产生界面反应。这将导致金属间化合物的形成，这将使接头脆化并无法使用。因此，开发用于连接不同合金组合的焊接工艺可以在塑造下一代部件体系结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，激光熔化工艺可以灵活地控制熔池形状，从而控制参与合金的混合。拟议的研究方案旨在为不同不同金属材料组合的连接制定可靠和变革性的激光连接技术。采用一种基本的科学方法，系统地识别和了解决定接头冶金特性和机械强度的关键支撑工艺因素。在拟议的研究方案中，将研究三种不同的不同合金组合。铁铝、钛不锈钢和镍镍不锈钢。根据不同工业部门的相关性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.