Friction consolidation of aluminum chips

In this paper, friction consolidation was applied on various aluminum chips (2xxx, 5xxx, 6xxx, and 7xxx series) with a rotating die and a stationary 'billet' chamber. Both components were made with H13 tool steel, and the die had a scroll pattern on the working end: similar to a 0° friction stir welding tool shoulder. In the friction consolidation process, the Z axis force was maintained constant and different rotational speeds from 100 rpm to 400 rpm were applied. Solid aluminum disks were obtained. The consolidation quality was evaluated from cross sections after grinding, polishing and etching processes. Micro-hardness testing was performed along the mid-plane of the cross section. The die rotation rate, required consolidating time, consolidating torque and power, consolidating quality, micro-hardness distribution, and relationship among those factors are discussed in this paper.