ENHANCING THE PROPERTIES OF ALUMINUM 7075 ALLOY WELDED JOINTS BY ADDING CONTROLLED FORCED LONGITUDINAL OSCILLATION

Aluminum alloys are in increasing demand as a structural and main purpose material in some of the most important industries of our times as aerospace and automotive industry, due to a new set of compliance demands, based on technical and financial efficiency with more and more rigorous environmental standards.

New aluminum alloys are under development, based on a wide range of possibilities to improve their characteristics by alloying or heat treating.

Our main goal in the present paper is to display the feasibility of the experimental results obtained by, exposing 2 aluminum 7075 alloy M.I.G. welded plates, to forced longitudinal oscillations at 50 Hz, propagated on the same direction and in the same time as the weld bed is forming, in comparison with the classic M.I.G. weld of the same alloy.Through the influence of parameters used in the experimental process and by comparison between the two welding procedures we intend to establish key enhancements in the microstructural integrity and mechanical properties of the weld. As microstructural changes are highly dependent on the frequency of wave phases, the study is aimed to the influence between longitudinal oscillations and the solidification of the melted metal pool.

As a result, the vibrations are enhancing the release of trapped gases and also the welded structure exhibitinga lower level of porosity with a higher grain refinement.

Micro-hardness tests were performed on both welded specimens to determine the difference in hardness of all welded regions and the way they influence the material.