Aluminum alloy 7075 was a star in the 1940s and for a good reason too. For the uninitiated, aluminum alloy 7075 has a strength that is comparable to many popular plates of steel that are on the market today, maintaining a great fatigue strength, high resistance to corrosion and average machinability. Not to mention it is one third the weight of steel.
With zinc as its primary alloying element, the alloy held a lot of promise in the early days of manufacturing. So what happened?
The process of welding aluminum alloy 7075 is no easy feat and almost impossible to uses to create some of the parts you may find down a factory line. Yet, the team of researchers from UCLA Samueli School of Engineering may have just developed a way to weld AA 7075.
Nanoparticles Are the Secret
When AA 7075 is heated at temperatures for welding, the molecular structure of the alloy creates an uneven flow of the elements it is comprised of, leading to the strength of the alloy being compromised and even cracking under heat.
Aluminum alloy 7075 is made of 5.6–6.1% zinc, 2.1–2.5% magnesium, 1.2–1.6% copper, and less than a half percent of silicon, iron, manganese, titanium, chromium, and other metals.
To tackle this problem, the UCLA team have used nanoparticles to fix this issue. Titanium carbide nanoparticles were infused into the alloy, using the nanoparticles as the filler material between two separate AA 7075 welding wires.
The new welded material was not compromised at all by cracks or weakened elements. In fact, the new weld of AA 7075 produced a tensile strength of about 392 megapascals. For reference, that would be the equivalent of some of the materials on aircraft used today.
The UCLA team believes that with a little experimentation that they could increase that tensile strength of the AA 7075 joints as high as 551 megapascals, rivaling steel.
With a material that is as strong as steel but lighter than steel, manufacturers could create faster and more fuel-efficient vehicles, and the usefulness does not stop there.
According to Xiaochun Li, UCLA’s Raytheon Professor of Manufacturing and the study’s principal investigator, “Companies could use the same processes and equipment they already have to incorporate this super-strong aluminum alloy into their manufacturing processes, and their products could be lighter and more energy efficient, while still retaining their strength.”