Microstructure evolution and ductility improvement mechanism of Fe-containing recycled brass alloy after Mn addition

Excessive Fe precipitates and accumulates during the reusing process of scrap brass, which affects the service performance of recycled brass. Therefore, eliminating the agglomeration of the rich-iron phase in scrap brass is significant research in the preparation of high-performance recycled brass. In this study, 0.4 wt%--0.8 wt%Mn was added in recycled brass containing 0.8 wt% Fe to eliminate the influence of Fe-rich precipitation on the as-cast and extruded brass. The results show that the introduction of Mn inhibits the precipitation of clover-like precipitates in the matrix and reduces the volume fraction of Fe-rich precipitates in as-cast brass. At the same time, the presence of Mn promotes the solid solubility of Fe in the brass matrix, and the solid solubility of Fe and Mn in the α and β phases is significantly different. For extruded brass, its ductility is significantly improved with the introduction of Mn and the strengthening process comes from the synergistic effect of solid solution strengthening and fine crystal strengthening. This study provides insight into the preparation of high-performance regenerated brass alloy with good ductility by eliminating the agglomeration of the rich iron phase in scrap brass.