Parts made from aluminum and titanium alloys are currently used in aircraft construction. Specialists from Belgorod State National Research University in Russia explained that reliable bonding of these parts would allow for the creation of high-strength, lightweight structures. Sergey Mironov, the leading researcher at the Laboratory of Mechanical Properties of Nanostructured and Heat-Resistant Materials, stated that at the contact point between aluminum and titanium blanks, chemical compounds of these metals, known as intermetallics, are formed.
Mironov said, “Due to their natural brittleness, intermetallics are one of the main reasons for welding failure. They cannot be completely eliminated, but the thickness of their layer can be reduced using alternative welding methods, such as Friction Stir Welding (FSW).” The scientists proposed “eliminating” direct contact between the working tool and the workpiece made of titanium, which led to excessive heat generation and contributed to the formation of a thick intermetallic layer.
The Friction Stir Welding technique involves the mechanical mixing of two welded pieces using a special tool that rotates at high speed. During the welding process, the materials of the parts heat up, and an intermetallic layer may form on the contact surface. Mironov stated, “This allows us to significantly reduce the intermetallic layer thickness, resulting in a substantial increase in the durability of welded joints. During mechanical tests, damage was detected in the aluminum blank area, not in the welding zone.”
He added, “Using this approach enables us to significantly lower the temperature at the cutting boundaries, thereby reducing the thickness of the intermetallic layer. As a result, we achieved a notable increase in the durability of welded joints. During mechanical tests, damage was observed in the original aluminum blank area, not in the welding zone.”
