According to its characteristics, the AA7075 aluminum alloy, developed in the 40s of the last century, has the strength of steel - but only a third of its weight. Unfortunately, its widespread use all this time was impossible, because it did not give in to welding. But now that will finally change.
The problem is this: the ingredients of AA7075 - aluminum, zinc, magnesium and copper - melt unevenly during the welding process. This phenomenon is called phase segregation, as a result of which cracks are formed along the entire length of the weld.
Recently, however, a team of scientists from the Samuel School of Engineering at the University of California, Los Angeles managed to develop the AA7075 welding technology.
They made thin rods from this alloy, to which titanium carbide nanoparticles were added. The rods were placed between the larger AA7075 pieces to be welded. In the process of arc welding, the rods and metal fragments began to melt - but thanks to the nanoparticles, already more evenly.
The result was welds with a tensile strength of 392 megapascals. For comparison, the same indicator for the traditional aluminum alloy 6061 - only 186 megapascals. Moreover, scientists have reason to believe that subsequent heat treatment can increase the strength of AA7075 welds to 551 megapascals. And this already corresponds to the strength of steel joints.
The AA7075 alloy is widely used in aircraft construction to create wings and fuselage. True, riveting has been used to connect individual parts into a single whole. With the advent of new welding technology, the possibilities for using the alloy increase significantly.