￼MATERIALS J-FAST: New alternatives for joining of dissimilar materials J-FAST Project developed new cleaner technologies based on form processes to enhance the unions between dissimilar materials. These unions are very common in industrial sectors such as automotive, power generation or appliances. Within this project, the partners expanded form processes to a number of materials (Aluminum alloys, steels and stain- less steels) and applications guarantying that the produced parts lead to similar properties of resistance in comparison to existing elements from conventional processes (drilling, threading). Friction riveting Expertise of the research carried out for the development of the FSW (Friction stir welding) process stated the concept that at the joints made by friction, therefore also in the case of riveting with hybrid effect (mechanical joint - friction welding), the following elements could be signi cant, as characteristics of the techniques used for the application : - Control of the downforce of the active element (FSW tool, rivet, pie- ces by classical friction welding) throughout the bonding process, especially when the rivet head touches the plate located above. - As it is a process which also produces a friction joint, as a result of the plasticization and mixing of materials, it is important to know and be able to hold a real-time control over the temperature at which the important sequences of the process are conducted. - Contrive and execution, especially of the bed frame and moving ele- ments of the equipment used in the application of the process must be completed in a robust structure and secure operation (vibra- tions introduced into the system during the process to be minimum values) - Base materials (parts to be joined) must be properly positioned and xed rmly, so that during the process no changes occur in the initial relative position of these. - Given the results obtained worldwide at ISIM Timisoara there were used different designs for rivets, which were tested in some preli- minary experiments. - Following these tests, promising preliminary results that may underlie the development of complex research were obtained using rivets design presented in gure 8. Figure 8. Rivet design of ISIM. A large program of experiments was performed to prove the possibili- ties of the friction riveting. Experiment no5 Overlaped sheets of aluminum alloy EN AW 7075, 5 mm thick and cop- per Cu 99 mm, 5 mm thick were used. The rivets were made of C45 steel, treated to 40-42 HRC, with M6 thread, having the active part length of 9 mm. Figure 9. Rivet joint appearance of the Experiment 5. The speed n = 1,450 rpm was used and the vertical displacement speed of the rivet was variable, with progressively increased values up to 20 mm/min. The direction of rotation of the rivet was counter- clockwise. The aspect of the joint made by the hybrid-riveting process is shown in the Figure 9. The characteristic aspects of the hybrid- riveting junctions are noted. Due to the characteristics of EN AW 7075 aluminium alloy, placed above, there is a ‘ring’ around the shoulder, of constant size and without chips (Figure 9). Experiment no9 Overlapped sheets of aluminum alloy EN AW 6082 (above), 3 mm thick and Cu99 copper, 3 mm thick were used. The rivets were made of C45 steel, heat treated to 40-42 HRC, with M6 thread, having the active part length of 5 mm. The rotational speed n = 1,450 rpm and the constant axial displacement speed of 15 mm/min of the rivet into the joints have been used. The direction of rotation of the rivet was anti-clockwise. The macroscopic aspect of the joint of the experiment 9 (Exp.9) is shown in the gure 10. 44<< Figure 10. Joint macroscopic appearance of the Experiment 9.