The Energy Balance in Aluminum–Copper High-Speed Collision Welding

Collision welding is a joining technology that is based on the high-speed collision and the resulting plastic deformation of at least one joining partner. The ability to form a high-strength substance-to-substance bond between joining partners of dissimilar metals allows us to design a new generation of joints. However, the occurrence of process-specific phenomena during the high-speed collision, such as a so-called jet or wave formation in the interface, complicates the prediction of bond formation and the resulting bond properties. In this paper, the collision welding of aluminum and copper was investigated at the lower limits of the process. The experiments were performed on a model test rig and observed by high-speed imaging to determine the welding window, which was compared to the ones of similar material parings from former investigation. This allowed to deepen the understanding of the decisive mechanisms at the welding window boundaries. Furthermore, an optical and a scanning electron microscope with energy dispersive X-ray analysis were used to analyze the weld interface. The results showed the important and to date neglected role of the jet and/or the cloud of particles to extract energy from the collision zone, allowing bond formation without melting and intermetallic phases.

Особенности разрушения ударников из пористого сплава на основе вольфрама с упрочняющим наполнителем при взаимодействии с бронепреградами

In this work, computational and experimental studies of the process of destruction of composite firing pin of porous alloy tungsten+nickel+iron+cobalt with 10 % content of titanium tungsten carbide at high-speed collision with steel barriers. It is shown that at ballistic tests with the broad range of speeds, significant exceeding of penetration of these firing pins in steel barriers in comparison with a mass-dimensional analog of the W-Ni-Fe-90 alloy. Based on the analysis of the crater morphology and structure of the striker fragments after penetration into the barrier, the assumption of implementation of the self-sharpenings mode of the firing pin, by means of localization of plastic deformation is made that leads to decrease in the effective area of interaction and increase in depth of penetration. Modification of a mathematical model of a porous ideal elasto-plastic solid with complex structure for the description of destruction with a possibility of accounting of the adiabatic shift mechanism in the course of interaction of the firing pin and a barrier is carried out.

Plastic Flow of Aluminum in Explosive Welding

Joining of metals in explosive welding takes place as a result of their plastic deformation during a high speed collision and is usually accompanied by typical formation of waves at the interface. In welding aluminium, the weld boundary can also be straight if the speed of the contact point is νc is ≤ 1900 m/s. These welding conditions make it possible to prevent melting of the metal at the interface and increase at the same time its corrosion resistance. In this article, the effect of the dynamic collision angle on the special features of plastic flow of the metal in the vicinity of the contact boundary in welding sheets of AS5 aluminium is described.