Evolution of hardness in recycled aluminum alloys with the aid of Equal Channel Angular Pressing (ECAP)

The present work investigated the influence of the pressing in equiangular channels (ECAP) in commercial aluminum in the form of recycled chip, the material was compacted and melted through a mold made of carbon steel. Three ingots (pure Al, dry chip Al, traditional chip Al) were produced giving rise to 18 samples which were deformed with 2 ECAP passes using the Bc route and room temperature in a matrix with a core built in tool steel. After deformed, the samples were submitted to Vickers microhardness, optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffractometry (XRD) analysis. The results indicated a significant increase in the hardness of the material after deformation, which is related to the presence of regions with high internal deformation, evidenced by elongated structures. The presence of aluminum oxide was also found in the upper part of the samples, although this component did not interfere with the levels of hardness observed. The legitimacy of the results of this study was verified through ANOVA (Analysis of Variance), in which the data were entered and processed using specific software. It can be concluded from this study that recycled chips from dry machining can be reused efficiently by applying appropriate casting processes associated with ECAP.