Characterization of mechanical and metallurgical properties of AA6063 foam developed by friction stir precursor deposition technique

Abstract

The aim of this work is to develop the precursor-based Al foam by deposition of AA6063-T6 consumable rod, filled with a foamable mixture of titanium hydrate (TiH2) and aluminium powder over a mild steel substrate through friction stir deposition (FSD) technique. The AA6063-T6 consumable rods were drilled with different hole strategies ranging from 1 to 6 holes on the periphery of the rod, which were filled with foaming powder of the same composition. To perform the deposition, a conventional vertical milling machine was used. The deposited material presents a fine equiaxed grain whose size is much lower than the as-received material, indicating dynamic recrystallization during friction stir deposition. The results also show that the foaming particles decrease the hardness values of the produced deposits when compared to those of base material. It has been observed that 4 and 5 numbers of holes in the consumable rod are more suitable for foam development and the foaming particles are more uniform as obtained from energy dispersive spectrum (EDS) and scanning electron microscope (SEM) analysis. It is also observed that by increasing the number of holes in the rod more than 5 promote the formation of defects in the developed foam. The consumable rod with 4 and 5 holes shows the linear plateau stress in the compressive test as compared to 1, 2, 3 and 6 holes.