Robust method for surface modulation in Cu-Zn alloys via pulsed laser surface melting

This study investigates the segregation behaviour of Zn in Cu-Zn brass during pulsed laser surface melting (pLSM), through a combination of experiments and molecular dynamics (MD) simulations. Understanding the segregation phenomena is critical for tailoring surface properties in alloys, which has significant implications for improving material performance in demanding applications. Starting from a Cu<inf>90</inf>Zn<inf>10</inf> random solid solution brass alloy, well-defined, Zn-rich annular regions that contain about 35 % Zn arise due to segregation during pLSM and subsequent solidification. MD simulations reveal that Zn atoms possess significantly higher mobility than Cu during both the melting and solidification stages, leading to pronounced surface segregation, corroborating experiments. This selective surface enrichment of Zn holds promise for enhancing corrosion resistance and surface hardness in brass alloys, paving way for further optimization of alloy compositions and laser processing parameters to achieve tailored surface properties in brasses and other alloy systems.