Laser surface engineering of copper with chromium for enhanced wear resistance

1. LSE of copper with chromium results into 1.5-3 times increase in average microhardness in the AZ than that of the substrate. 2. The AZ contains 2-8at% chromium in total, with 1-3.5at% chromium in solid solution. Furthermore, chromium-precipitates amount to 4-13% of the area in the microstructure of the AZ on the cross-sectional plane. 3. LSE extends the solid solubility limit of chromium in copper to 3.5at%. 4. The increase in hardness is attributed to both solid solution and dispersion strengthening with the former being more effective. 5. The optimum condition of lasing corresponding to the maximum average microhardness in the AZ are: t = 10 μm, Q = 1 GW/m2 and v = 0.25 m/min. 6. LSE (in optimum condition) reduces the wear loss by more than an order of magnitude than that of pure copper.