Laser welding of aluminium alloys and dissimilar metals

A laser is a heat source with a high power density; laser welding has been gaining recognition as a method superior in quality, precision, resistance to deformation, flexibility, speed and productivity. It can be applied to robotisation, automation, systemisation and line production as well as the reduction of energy consumption. In laser welding of aluminium alloys (which has already been applied to welding in some fields) much expectation has been held for the expansion of its uses. In addition, since industrial products have more sophisticated functions, higher performance, higher quality, and so on, there has been an increased need for the welding of dissimilar metals such as aluminium alloys and steels. The conventional view over the combination of dissimilar metals such as aluminium, and steels in which intermetallic compounds are produced, has generally been that it is very difficult or almost impossible to weld or join them together. Recently, however, the welding of combinations of materials such as aluminium alloys and steels or titanium alloys, and of magnesium alloys and steels, has been conducted using high performance YAG laser, semi-conductor laser, or CO 2 laser to carry out investigations into various aspects such as the position and method of laser irradiation, the shapes of joints and the state of fusion. There have been reports that good weldability can be obtained if the fusion of each material can be controlled at the interface of the joint or if only light metals can be fused. Therefore, in this article, an introduction is given of recent results published on the laser welding of aluminium alloys and dissimilar metals.