An innovative technique for the industrial sector has been achieved by
Heriot-Watt University scientists who have fused metal and glass together
with an ultrafast laser system.
Using the Heriot-Watt laser system, which delivers very short, picosecond
pulses of infrared light in tracks along the materials to fuse them
together, a variety of optical materials, including quartz, borosilicate
glass, and even sapphire, have been successfully welded to metals, including
titanium, aluminum, and stainless steel.
The new method has immediate applications in the sectors of optical
technology, aerospace, defense, and even healthcare, and it has the
potential to completely change the manufacturing industry.
Director of the five-university EPSRC Centre for Innovative Manufacturing
in Laser-based Production Processes at Heriot-Watt, Professor Duncan Hand,
stated: "Due to their dissimilar thermal properties, it has historically
been very difficult to weld together dissimilar materials like glass and
metal—the high temperatures and highly different thermal expansions involved
cause the glass to shatter.
The ability to fuse metal and glass together will greatly increase
production and design flexibility.
Currently, adhesives are frequently used to hold together machinery and
items using glass and metal. These adhesives can be messy to apply and cause
pieces to progressively creep or shift. Another concern is outgassing, which
can cause a product's lifespan to be shortened by the adhesive's organic
compounds gradually releasing.
The extremely brief laser pulses are essential to the procedure. These
pulses endure only a few picoseconds; in comparison, 30,000 years is
equivalent to a second to a picosecond.
We obtained megawatt peak power across an area of a few microns wide by
placing the components to be welded in close proximity to one another and
focusing the laser through the optical material to generate a very small and
extremely intense spot at the interface between the two materials.
As a result, a highly constrained melt area encircles a microplasma—like a
little ball of lightning—that forms inside the material.
"We know the welds are robust enough to handle extreme conditions because
we tested them at -50C to 90C and the welds remained intact."
Provided by
Heriot-Watt University
