Surface morphological, electrical and mechanical properties of nanosecond & femtosecond laser exposed copper, zinc and cupronickel

Abstract

Effect of laser irradiation on different properties of copper, zinc and their alloy cupronickel (79% copper, 20% zinc and 1% nickel) is investigated. Experimentation is carried out in two portions. Firstly, polished samples are treated with Nd:YAG laser (1.064 µm, ∼12 ns, 10 mJ) in air at different number of laser pulses (10, 20, 30) by making grid on sample. In second portion of experiment, the samples are irradiated separately by Ti:sapphire laser (800 nm, ∼25 fs, ∼0.012pJ) for different exposure time (30, 60 and 90 min). After laser exposure, the surface modifications, electrical conductivity and hardness are analyzed using optical microscope, four-point probe equipment and Vickers hardness tester respectively. Nanosecond laser exposure causes surface roughness, nonuniform heat conduction from crater to outer edges, formation and melting of ripples and heat-affected zone. Laser irradiation leads to decrease in electrical conductivity of the target materials. Laser treatments causes non-linear increase of hardness inside the target materials.