Abstract
In the present study, powder metallurgy processed unmilled AlMg5 (AlMg5-UM), milled AlMg5 (AlMg5-M), and milled AlMg5–0.4vol.% Al2O3 (AlMg5–0.4Al2O3) nanocomposite were successfully spark plasma sintered at 550°C. The microstructural analysis of spark plasma sintered AlMg5-UM revealed equi-axed grains with average size of 20±5μm. The microstructural analysis of spark plasma sintered AlMg5-M and AlMg5–0.4Al2O3 revealed a bimodal grain structure with both fine-coarse grains of size 700nm–8μm and 300nm–8μm, respectively. The spark plasma sintered AlMg5-UM exhibited a yield strength (YS) of 132±3MPa, ultimate tensile strength (UTS) of 296±2MPa and % elongation (% El) of 22±2 comparable to the conventional Al 5083 alloy — O temper (YS of 145MPa, UTS of 281MPa and % El of 16). The spark plasma sintered AlMg5-M and AlMg5–0.4Al2O3 exhibited YS of 242±9MPa and 274±5MPa, UTS of 376±4MPa and 417±8MPa and % El of 19±1 and 10±1, respectively. The lower strength (YS and UTS) of AlMg5-UM can be ascribed to its coarse grains. Among the milled samples, the AlMg5–0.4Al2O3 composite exhibited high strength and it can be ascribed to its fine grain size (Hall–Petch effect), higher dislocation density and Orowan strengthening effect due to Al2O3 reinforcements.
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•The spark plasma sintered unmilled AlMg5-UM, milled AlMg5-M and AlMg5–0.4Al2O3 samples revealed fine equi-axed grains.•The milled samples (AlMg5-M and AlMg5–0.4Al2O3) exhibit higher strength and hardness compared to AlMg5-UM samples.•High strength of milled samples achieved through grain refinement, dislocation and Orowan strengthening•The nanocomposite AlMg5–0.4Al2O3 exhibited YS of 274MPa compared to the conventional Al 5083 alloy (YS: 145MPa).