This is one of those things that just doesn’t sound like it should work at all: Somehow melting together glass and metal to combine into one, unified, part-glass/part-metal mongrel whole. If it could be done, it would be a breakthrough for automobile manufacturing, which is all about combining glass and metal. Well, it seems that researchers at Edinburgh, Scotland’s Heriot-Watt University have figured it out. With lasers.
Professor Duncan P. Hand and his research team have developed a process called “ultrafast laser microwelding,” which uses very, very short pulses of infrared laser light to fuse two dissimilar materials together. The Heriot-Watt system tested the method on quartz, borosilicate glass, sapphire and aluminium, titanium, and and stainless steel.
Professor Hand described the process to Phys.org:
“The process relies on the incredibly short pulses from the laser. These pulses last only a few picoseconds—a picosecond to a second is like a second compared to 30,000 years.
The parts to be welded are placed in close contact, and the laser is focused through the optical material to provide a very small and highly intense spot at the interface between the two materials—we achieved megawatt peak power over an area just a few microns across.
This creates a microplasma, like a tiny ball of lightning, inside the material, surrounded by a highly-confined melt region.
We tested the welds at -50C to 90C and the welds remained intact, so we know they are robust enough to cope with extreme conditions.”
Currently, most auto glass is held in place with adhesives, which adds layers of complexity to manufacturing and can outgas and degrade as a car ages. Being able to directly weld panels of, say, glass and aluminium could open up many interesting possibilities for auto design and manufacturing.
Of course, it also brings up the question of replacement: Could a local body shop still replace a window if one breaks, or would a whole new panel, with the window welded in, need to be sourced? Would differing rates of thermal expansion be an issue for these hybrid body parts?
I’m sure there will be all kinds of testing to answer these questions, and this is still a long way off from going into production, but it sure is interesting.