Aluminum Alloys with the Addition of Reduced Deep-Sea Nodules

Possibilities of a Direct Synthesis of Aluminum Alloys with Elements from Deep-Sea Nodules

This work investigated the possibility of the direct preparation of aluminum alloys by aluminothermic reduction of deep-sea nodules with a high excess of aluminum. The process was found to be unable to obtain aluminum alloy, but an aluminum-rich manganese-based alloy was obtained instead, being composed of intermetallics. The alloy was characterized in the as-reduced state, as well as after crushing and sintering in the temperature range of 800–950 °C. The sample sintered at 900 °C was also heat-treated by annealing at 800 °C for 3 h and rapidly cooled. It was observed that with the increasing sintering temperature, the original matrix phase Al₁₁Mn₁₄ was transformed into a duplex matrix with a structure corresponding to Al₁₁Mn₁₄ and Al₄Cu₉, and this mixture was further transformed to the matrix with the structure corresponding to Al₄Cu₉. Furthermore, the mechanical properties and wear resistance of the samples were described. The highest microhardness was reached in the sample, which was annealed after sintering. Sintered samples reached a lower wear rate because of the fragmentation of brittle intermetallics during crushing.