Laser surfacing of brass with Ni–Cr–Al–Mo–Fe using various laser processing parameters

Brass (Cu–38%Zn) specimens were laser surface modified with Ni–Cr–Al–Mo–Fe (Ni–10%Cr–7%Al–5%Mo–5%Fe–1%B) using a 2 kW CW Nd:YAG laser. Successful laser surfacing was achieved with a power density around 70 W mm−2, a scanning speed in the range 15–35 mm s−1, and a 50% overlap of adjacent tracks. The hardness of the alloyed layer increased as the dilution ratio decreased. The cavitation erosion resistance, defined as the reciprocal of the mean erosion rate, of the modified specimens in 3.5 wt.% NaCl solution (pH 6) at 23 °C was improved by a factor in the range 2.47–4.60 compared with that of brass, and correlated well with the hardness. The improvement in the cavitation erosion resistance was attributed to the formation of hard boride phases in a ductile Ni-rich matrix. On the other hand, there was no significant improvement in the corrosion resistance.