MICROSTRUCTURE EVOLUTION AND PROPERTIES IMPROVEMENT OF Fe-CONTAINING SCRAP BRASS ALLOY BY Al MICROALLOYING AND DISPERSION DISTRIBUTION REGULATION

During the production of recycled brass, trace amounts of Fe in the scrap brass stream can accumulate and, upon melting can precipitate and agglomerate in the matrix, which affects the performance of the brass. Microalloying control by adding trace amounts of other elements is expected to mitigate the effect of iron-rich phase agglomeration and improve the mechanical properties of recycled brass. This work added a small amount of Al (0.4-0.8 wt%) to improve the performance of Fe-containing brass (0.6 wt%) in cast and extruded states. It was found that the addition of Al changed the form, morphology, and type of the original Fe-rich precipitated phase. In the metallographic structure, Al was mainly combined with Fe in the matrix to form fine Fe3Al intermediate compounds. The hardness of as-cast brass was harder by the evolution of structure. Adding Al significantly improved the agglomeration behavior of the precipitated phase and enhanced the dispersion distribution characteristics. The reason for dispersion distribution was analyzed, which is the synergistic action of interfacial energy and capillary action energy. The mechanical properties of extruded states under a high extrusion ratio with different contents of Fe-Al microalloying were studied. For the extrusion state, the addition of Al significantly improved the mechanical properties of brass, including tensile and torsional properties. This study can provide a reference for microstructure control and property optimization of recycled brass. [GRAPHICS] .