Traditionally, materials with similar properties become "participants" in the welding process. For example, welding plastic to steel is still problematic. The main difficulty in welding different materials lies in their different melting temperatures.
However, scientists at Heriot-Watt University (Edinburgh, Scotland) have learned to connect seemingly incompatible, using an ultrafast laser pulse instead of electrodes.
The new technology is based on the use of optical materials such as quartz, borosilicate glass and sapphire, which can be welded to aluminum, stainless steel and titanium. The process became possible thanks to an infrared laser that emits pulses with a frequency of several picoseconds.
The parts to be welded are superimposed on each other, after which the laser focuses on them through the optical material, creating a very intense heating spot at the interface between them.
This generates a peak power of about a megawatt over an area of several microns. The result is a microplasma that resembles a tiny ball of lightning within the material, surrounded by a minor melt zone. Thanks to this, welded seams are formed that remain reliable and durable at temperatures from –50 to +90 ° C.