Engineers from the Max Planck Society in Düsseldorf and the Fraunhofer Institute for Laser Technology in Aachen (Germany) have developed a new technology for creating heterogeneous microstructures using 3D printing. To visualize their work, they printed an analogue of the famous Damascus steel. This is not a blank for a weapon, there is no need to talk about the outstanding performance of the material, it was made precisely to demonstrate how ancient technologies can be transferred to the modern world.
The main distinguishing feature of Damascus steel is the alternation of many layers of hard and soft metal inside a single package. In classic forging, these layers were first made in the form of separate fragments, and then joined together. The 3D printing method involves the application of different layers in succession in order to eventually repeat the same structure. However, classic Damascus steel uses two types of raw materials with different chemical compositions, which is still too difficult for modern 3D printers.
German scientists used a single raw material - a powder of an alloy of iron, nickel and titanium, but equipped the print head of the printer with an additional laser emitter. During printing, the powder melts and spreads in a layer of a given thickness over the workpiece, after which a pause is made to allow this fresh layer to cool below 195 ° C. Then, with the help of a laser, the upper part of this layer is instantly heated and the next layer of molten metal is immediately fed on top of it.
Due to the fact that in each layer individual areas cool differently, the mechanical properties of the finished metal also change - the same alternation of hard and soft layers is obtained. But the main nuance is that when reheating with a laser, you can very accurately influence the microstructure of the metal and thereby create sections of the product with very different properties right during printing. It is this "design" of new alloys on the go that German engineers call a real achievement. And the replica of Damascus steel is just a visual demonstration of the idea.