Preliminary evaluation of the influence of copper from reprocessed scrap on the microstructure, hardness and compressive strength of zamac 5

ABSTRACT

Zamac is a metallic alloy composed of zinc, aluminum, magnesium and copper. Its processing properties, such as low melting point and high hot fluidity, make the industry reprocess the waste from zamac production without sending it to a plant for refining, which can cause differences in chemical composition in the original alloy and consequently in its mechanical and microstructural properties. This work aims to evaluate the variations arising from the reprocessing of zamac 5 in the form of scrap containing alkaline copper electrodeposition in terms of microstructure and mechanical properties. The reprocessed samples were compared with zamac 5 samples as received and analyzed using hardness, compressive strength, microstructure tests using scanning electron microscopy and chemical composition tests using EDS. The results of the compressive strength and chemical composition tests show that a new alloy was formed, with an increase in copper concentration of approximately 4%, very similar to the ternary alloy Zn-15Al-4Cu. Although this new alloy has shown results of high hardness and relatively low compressive strength, preliminarily, it can be said that it is suitable for manufacturing parts that do not receive significant compressive stresses, such as decorations for clothes, bags, shoes and accessories.

Keywords
Zamak; Reprocessing; Microstructure; Mechanical properties