EBSD investigation of Al/(Al₁₃Fe₄+Al₂O₃) nanocomposites fabricated by mechanical milling and friction stir processing

Abstract

The application of ball-milling for reactant powders (Fe O +Al) to form in situ nanosized reaction products in the stir zone of 1050 aluminium alloy was examined and the evolution of microstructure, grain boundaries and microtexture of the fabricated Al/(Al Fe +Al O ) nanocomposite was investigated. The mean matrix grain size of the fabricated nanocomposites by the combination of ball milling and friction stir processing were found to be ∼3.2, 3.1 and 2.1 μm for 1, 2 and 3 h milled powder mixtures, respectively. The fraction of high-angle grain boundaries increased markedly in the stir zone indicating the occurrence of dynamic restoration of the aluminium matrix. This was also associated with increasing of the fraction of low ∑CSL boundaries. In addition, the fraction of high-angle grain boundaries increased as the reaction product increased. The developed textures were compared with the most important deformation and recrystallisation texture components of cubic close packed structure. Some of the main texture components formed due to the restoration of aluminium in the stir zone of the material with no powder addition were Cube {001}<310>, BR {236}<385> and R (or retained S{123} <634>); these are usually found in the rolled materials. However, the presence of nanosized reaction products in the fabricated nanocomposite changed the texture components to the dominant Goss {011}<100>, P {011}<122> and R{124}<211> textures.

Electron backscattered diffraction analysis of friction stir processed nanocomposites produced via spark plasma sintering

“…These results clearly implied that the presence of alumina with bimodal size particles have two remarkable effect: first the nucleation via PSN, for particles greater than 1 µm and second preventing subgrain growth of aluminium matrix via restricting the dislocation movements. Such results are consistent with the findings of Azimi et al (2018).…”

“…However, it can be found that the mean grain size is strictly influenced by the amount of the heat input that is proportional to the rotational to travelling speed ratio. Moreover, the microstructural feature in the SZs grains of all FSW conditions showed that the rotational speed have more significant effect with respect to the travelling speed on the heat input and occurred dynamic recrystallisation (Azimi‐Roeen et al ., ).…”

Remanufacturing the AA5052 GTAW Welds Using Friction Stir Processing

“…SZ is composed of fineequiaxed recrystallised grains. The fine recrystallised grains at the SZ are formed due to severe plastic deformation, followed by dynamic recrystallisation resulting from the thermo-mechanical processing [12,15,31,32].…”

“…The misorientation at LAGBs rises steadily until the transient to HAGBs happens. The LAGBs transforming rate depends on the pinning of subgrain boundaries [31,[33][34][35]. After an apparent deformation level, the sub-boundaries are pinned by precipitates in the matrix (or effect of some solid solution elements).…”

Archives of Metallurgy and Materials

“…The multiple passes with 100% overlapping in same traverse direction and with change of traverse direction were reported useful. The tool materials used in FSP of this series were H13 steel [32,[35][36] and D2 die steel [33]. The pin probe shapes like threaded straight cylindrical [32][33], square [36] and conical threaded [37] were used.…”