EVALUATION OF LASER TREATED COPPER-ALLOYS

Copper alloys of composition Cu-35Zn-3Pb and Cu-31Ni-1.9Cr were laser treated and characterised using optical and scanning electron microsco py and stress corrosion experiments. Laser induced defects in the form er alloy increased the variability in the time to failure by stress co rrosion cracking in the laser treated specimens relative to the bulk. The latter alloy, when laser treated, has a defect free surface which is more resistant to pitting in sea water than that of the bulk and is not susceptible to stress corrosion cracking despite the stress corro sion cracking sensitivity of conventional gas metal arc welds in this alloy. Practically, the results suggest that laser induced defects may limit the acceptable process window of laser treated copper alloys in tended for use in sea water.